Spellcasting Consequences

[Spider_Jerusalem]

So... "magic is dangerous" is actually a very common trope in most of fantasy, and I feel D&D doesn't actually emulate that well. Of course, there are cursed items and monsters created by accident, but the players don't really experience the "dangerous" part of casting spells. If you wanted to simulate consequences for magic, what would you do, both mechanically and fluffwise?

[psi51]

How about a critical fumble/hit table for concentration checks,
or allow a player to cast extra spells a day but take cumulative damage per extra spell level,
Or have a look at primal magic in pathfinder or wild magic in 3.5.

[Slipperychicken]

There are a lot of questions to answer here, before anything productive can happen. Firstly, what do you want to accomplish (thematically and/or mechanically) with these "consequences"?


Why are there consequences? Is there some entity repressing it (and if so, what is it and why)? Is magic dangerous in and of itself? Does using magic open the world to some cosmic horrors?

Is magic safe in moderation, but dangerous in excess? Should it be dangerous to anyone who tries it? Does it become safer as a magician masters it? How does one master it?

When is it safe, and when is it dangerous?

Are there precautions which can mitigate magic's downsides? (Here I'm thinking about setting rituals up, summoning circles, assistants, properly-arranged candles, etc)

Are the dangers primarily physical or psychological in nature? Do magicians become feeble? Do they go insane?

Should the dangers be a slow and subtle? Or immediate and obvious?

[jackattack]

Critical failures on concentration checks, resulting not in spell failure but in the spell having detrimental results. A fireball would go off in the caster's face, mirror image would affect an opponent, magic missile would target allies, and so on.

Accelerated aging. Every time a spell is used, the caster ages spell-level weeks. Eventually, they will start to hit age-related stat penalties.

Magic attracts monsters and demons, who might hound or even attack the caster. Not so easy to cast in combat when the quasit who's been following you gives you a wedgie. And hard to justify using a high-level spell in combat when it might attract an arcane elemental who will drag you off to the elemental plane of magic forever.

[Feralventas]

HP damage = The spell level squared.

Magic Missile= 1 point of damage, 1^2=1.
Levitate= 4 points, 2^2=4.
Fireball= 9 points, 3^2=9.
Greater Invisibility= 4^2=16.

And so forth.

On a critical failure of a concentration check or if the spell is interrupted, the spell fails and the HP damage is multiplied by the caster level.

This damage may not be mitigated by any means nor re-directed regardless of the method used. It is treated as lethal even through Regeneration, and it eats through normal hit-point pools and ignores temporary HP.

[King Atticus]

HP damage = The spell level squared.

Magic Missile= 1 point of damage, 1^2=1.
Levitate= 4 points, 2^2=4.
Fireball= 9 points, 3^2=9.
Greater Invisibility= 4^2=16.

And so forth.

On a critical failure of a concentration check or if the spell is interrupted, the spell fails and the HP damage is multiplied by the caster level.

This damage may not be mitigated by any means nor re-directed regardless of the method used. It is treated as lethal even through Regeneration, and it eats through normal hit-point pools and ignores temporary HP.

This seems ridiculously harsh considering that a Wizard gets 9th level spells at level 17 and has a D4 hit die. A 9th level spell by your outline would do 81 points of damage which is 13 points more than the caster would have at level 17 IF he rolled max HP every level (If he has a +0 con). That amounts to cast a spell a die from the trauma. :smallfrown:

[Reluctance]

Use a system other than D20. The flat probability "curve" does not give you a system where critical successes/failures can feel especially important, and the predictability of D&D style spellcasting means that the bad effects can be predicted and most effectively mitigated.

If I had to work within the D20 mechanic, I'd either ban fullcasters or nerf them such that top-level spells did not exist in the Vancian mechanic, as well as removing choice other spells across the spell levels, and move those to the incantation system. You can have your Magic Missiles without unleashing cosmic horrors on the party. (I'm not a big fan of having basic character features come with crippling drawbacks.) Teleporting, binding an outsider, or creating an extraplanar sanctum, those you have to make an extended check for. The better you roll, the better your results and the fewer things that try to eat your face.

[Feralventas]

This seems ridiculously harsh considering that a Wizard gets 9th level spells at level 17 and has a D4 hit die. A 9th level spell by your outline would do 81 points of damage which is 13 points more than the caster would have at level 17 IF he rolled max HP every level (If he has a +0 con). That amounts to cast a spell a die from the trauma. :smallfrown:

The 'casting classes are undeniably the most powerful classes in the game. Making them pause every other round after casting one of their most potent abilities to drop a Heal spell on themselves via one method or another (and there are methods available to Wizards as well).

In addition, it is well within the means of a 'caster with 9th level spells to have buffed their Constitution to or above +5 minimum (decent base stat roll, enhancement bonuses, inherent bonuses, and shape-shifting effects).

I figure risking death for the power to play god is about fair.

[umbergod]

The 'casting classes are undeniably the most powerful classes in the game. Making them pause every other round after casting one of their most potent abilities to drop a Heal spell on themselves via one method or another (and there are methods available to Wizards as well).

In addition, it is well within the means of a 'caster with 9th level spells to have buffed their Constitution to or above +5 minimum (decent base stat roll, enhancement bonuses, inherent bonuses, and shape-shifting effects).

I figure risking death for the power to play god is about fair.

Emphasis mine. If magic is that risky, and they're low on health, what would make them eager to use a heal spell and risk killing themselves by failing to cast it. Potions, wands, staves, and perhaps scrolls would be the only real save, and that depends on how the dm rules casting spells from items

[DoughGuy]

HP damage = The spell level squared.

Magic Missile= 1 point of damage, 1^2=1.
Levitate= 4 points, 2^2=4.
Fireball= 9 points, 3^2=9.
Greater Invisibility= 4^2=16.

And so forth.

On a critical failure of a concentration check or if the spell is interrupted, the spell fails and the HP damage is multiplied by the caster level.

This damage may not be mitigated by any means nor re-directed regardless of the method used. It is treated as lethal even through Regeneration, and it eats through normal hit-point pools and ignores temporary HP.
EMphasis mine. Are you saying that the 9*9 damage for casting a level 9 spell, if interrupted would be multiplied by 20? Thats over 1600 damage. Thats unreasonable. A level 5 spell at CL 9 would deal 225 damage if failed. Sure its a 1/20 chacne but that is going to happen at soem point. You are basically saying sur eyou can play are caster, but you are already dead, you just dont know how long you have left.

[Feralventas]

Emphasis mine. If magic is that risky, and they're low on health, what would make them eager to use a heal spell and risk killing themselves by failing to cast it. Potions, wands, staffs, and perhaps scrolls would be the only real save, and that depends on how the dm rules casting spells from items

Magic items are pretty easy to come by if you go by the real WBL rules and treat GP as a secondary XP chart. Potions, wands, and Staffs can be crafted or bought at the Player's discretion and would be a viable balance to the dangers of spell-casting.


Emphasis mine. Are you saying that the 9*9 damage for casting a level 9 spell, if interrupted would be multiplied by 20? That's over 1600 damage. That's unreasonable. A level 5 spell at CL 9 would deal 225 damage if failed. Sure its a 1/20 chances but that is going to happen at some point. You are basically saying sure you can play are caster, but you are already dead, you just don't know how long you have left.

A 5th level 'caster can wreck a city-block with their daily spell-set if they decide to focus on it. A 20th level one is well beyond world-changing spells and abilities. Handing out save-or-die spells with no risk in doing so? That's unbalanced. Having a chance of magical feed-back that will rend you asunder? Still an acceptable risk considering it's only a 5% chance.

It should also be stated that skill-checks do not fail, so a critical failure of a concentration check would have to be a check that failed to succeed; a natural 1 would not invoke this, but 'casting recklessly would. I apologize for wording that poorly.

[Mnemnosyne]

Without making it so that magic is unreliable, all that can really be done is add a physical cost of some kind to magic. Since I think player abilities generally should not be made more unreliable, introducing a physical cost of some sort is definitely the route I'd go. Something along the lines of the Channeller variant from 2nd Edition Player's Option: Spells & Powers seems like it would work well.

The channeller was a spell point using variant that could recharge spell points throughout the day rather than having to only regain spells at night. Any time she wasn't exerting herself, she could regain spell points (slowly, mind you, but she was regaining them). The trick is that every spell they cast increases their fatigue - especially their more powerful spells. A 9th+ level wizard can cast 1st level spells without fatigue, but 2nd level spells induced light fatigue, 3rd and 4th induced moderate fatigue, 5th caused heavy fatigue, and 6th caused severe fatigue. 7th and higher would cause mortal fatigue. Casters under this system actually could cast spells higher than their level would normally allow, but if you ever hit 'mortal fatigue' you had to make a saving throw or instantly die (and even if you succeed in the saving throw you wind up unconscious for 1d6 hours).

As long as the players aren't given any way to mitigate this fatigue, or at least the ways to do so are very strictly limited, the system seems to stick to many of the classic tropes of spellcasting. Able to use a variety of spells at-will rather than specific pre-memorized ones (it actually used a combination of fixed and free magicks, with fixed being pre-memorized spells and free being any spell from your book, but free costs more spell points to cast), tires a caster out and puts them in actual physical danger if they cast powerful spells, and even allows them to exert themselves beyond the limits of their ability, but probably die in the attempt.

[Slipperychicken]

Having a chance of magical feed-back that will rend you asunder? Still an acceptable risk considering it's only a 5% chance.

No, it's not an acceptable risk. It's forcing Wizards to play Russian Roulette to do their jobs. Anyone who values his life would not cast those spells.



Handing out save-or-die spells with no risk in doing so? That's unbalanced.

Why hello there, Massive Damage (http://www.d20srd.org/srd/combat/injuryandDeath.htm#massiveDamage).

If you don't like Save-or-Die (I don't like it, myself), ban it, or use one of the variants. Adding more save-or-die effects will only make the problem worse.

[limejuicepowder]

Magic items are pretty easy to come by if you go by the real WBL rules and treat GP as a secondary XP chart. Potions, wands, and Staffs can be crafted or bought at the Player's discretion and would be a viable balance to the dangers of spell-casting.



A 5th level 'caster can wreck a city-block with their daily spell-set if they decide to focus on it. A 20th level one is well beyond world-changing spells and abilities. Handing out save-or-die spells with no risk in doing so? That's unbalanced. Having a chance of magical feed-back that will rend you asunder? Still an acceptable risk considering it's only a 5% chance.

It should also be stated that skill-checks do not fail, so a critical failure of a concentration check would have to be a check that failed to succeed; a natural 1 would not invoke this, but 'casting recklessly would. I apologize for wording that poorly.

Eh, it still means that spellcasters will routinely be forced to make checks that could result in their immediate death; whatever the percent chance of that failure is largely irrelevant. As long as it's statistically reasonable, say 1/500 (it will be a great deal higher then that without concentration boosting cheese), the chances of spellcasters making it to even the mid levels is very small. And that's not even counting in the normal hazards of adventuring.

The point is that most people would object, and reasonably so, to have a save-or-die mechanic built in to their class abilities, regardless of the power it offered. Really, how fun is it to play a character that could die at any time just by trying to do the things the class should do?

[navar100]

For D&D, this concept doesn't work for the same reason critical fumbles sucks donkey for warriors. PCs are on camera all the time. Eventually the law of averages will hit and a PC will suffer big time.

A player character should not be punished for the audacity of doing what he's supposed to be doing.

[Gamer Girl]

So... "magic is dangerous" is actually a very common trope in most of fantasy, and I feel D&D doesn't actually emulate that well. Of course, there are cursed items and monsters created by accident, but the players don't really experience the "dangerous" part of casting spells. If you wanted to simulate consequences for magic, what would you do, both mechanically and fluffwise?


Magic in may game is dangerous.

1.All Ye Old 2E Consequences are in Effect. See before 3X there was this D&D game called 2E. And in that edition magic was dangerous, there where all sorts of penlites and bad effects of spellcasting. But 3X wiped them all away to make the game 'easier' and 'more friendly to kids'(or something). For example, in 2E, if you changed your bodies shape, you have to make a shock roll or die.

2.Strange Effects In short, wild magic is common. When spell resistance 'blocks' a spell, for example, the magic does not just go away...something will happen. The same is true for making a save too.

3.Laws of Magic This is my huge list of 'mixing magic' and such. For example, it's only safe to use necromancy spells on living creatures of close to your type. For example, a human can drain hit points from a dwarf. But other creatures can cause all sorts of things can happen.

[Batou1976]

Think carefully before giving magic such consequences. I heartily agree there should be some sort of price for using powerful high level magic (beyond gp and xp costs), but I also don't think it would be much fun to play a wizard whose life got mostly sucked away by casting Trap the Soul and Time Stop too much.

Magic should not only be dangerous to target and caster, IMO. In much fantasy literature and folk tales, it's also somewhat unpredictable and unreliable. I've always been annoyed by the ability of a wizard PC to cast Fireball and BOOM! auto-damage to the monsters, while the martial characters have to make an attack roll every time they want to hurt something.

Can we also come up with something along the lines of making spells not so 100% reliable (barring SR and passed saves)? Gamer Girl, like your #2 and 3 points. Care to elaborate?:smallbiggrin:

[Spider_Jerusalem]

There are a lot of questions to answer here, before anything productive can happen. Firstly, what do you want to accomplish (thematically and/or mechanically) with these "consequences"?

Lots of relevant questions here.

Yes, I believe the first step to introduce any kind of houserule is finding out why you want it, and I agree with most of your questions there. Even though I was asking in a general way, those questions you posed can help a lot when deciding to try new ways to use this "majick" thing.

I used some variants I found interesting in a few games, ranging from "blood magic" (casters didn't have spells per day nor a MP bar. Instead, they spend HP to cast. "Healing" was, obviously, not a kind of magic. Spending too many points left your character fatigued or exhausted) to "demonic contract magic" (casters received magic from demon lords, and for each spell they had to "pay" some price to him. This price could be paid by specific and lengthy rituals for each spell, or by trading the power for some of your own vital force - which meant taking ability damage to cast. Casting spells also required a Spellcraft check. In case of failure, the demonic entity would control your character for a number of rounds equal to the spell level. Each spell cast would make the next spellcraft check made before resting a bit harder. Failing your check for a level 9 spell would make your caster exchange places with the entity, being sucked into a portal to hell, while the demon escaped from it).

It was usually fun.


Magic in may game is dangerous.

1.All Ye Old 2E Consequences are in Effect. See before 3X there was this D&D game called 2E. And in that edition magic was dangerous, there where all sorts of penlites and bad effects of spellcasting. But 3X wiped them all away to make the game 'easier' and 'more friendly to kids'(or something). For example, in 2E, if you changed your bodies shape, you have to make a shock roll or die.

2.Strange Effects In short, wild magic is common. When spell resistance 'blocks' a spell, for example, the magic does not just go away...something will happen. The same is true for making a save too.

3.Laws of Magic This is my huge list of 'mixing magic' and such. For example, it's only safe to use necromancy spells on living creatures of close to your type. For example, a human can drain hit points from a dwarf. But other creatures can cause all sorts of things can happen.

See, I was a 2E player myself, and I actually wanted to bring back some of that stuff. I think magic sounds less impressive when it's just another ability your character has. In 3.x rules, magic is not actually mysterious.

I'm currently DMing a campaign and I was thinking about creating random reactions for high "magical exposure". The downside is that it makes magic sound somewhat like just a fantasy kind of radiation, though, haha.

[Andorax]

It's minor, but I was toying with an idea a while back for something along these lines for Psions.

If you pp drop below your ML (or 1/2 ML for Psywars), you become fatigued, and can't recover that fatigue until you get your points back up.

If you hit 0, you can tap an "inner reserve" equal to that same breakpoint (drop to negative PP equal to your ML or 1/2 ML), but doing so causes you to become exhausted (again, not recovering from it until your points come back up) and take damage equal to PP spent).

[Slipperychicken]

Yes, I believe the first step to introduce any kind of houserule is finding out why you want it, and I agree with most of your questions there. Even though I was asking in a general way, those questions you posed can help a lot when deciding to try new ways to use this "majick" thing.


Here's one thought.

You could try making a table (or just stealing one of those countless mishap tables lying around) of relatively benign effects (not too harsh, stuff that a level 1 Wizard could plausibly survive. The Rod of Wonder could be some inspiration, with things like turning purple or summoning swarms of harmless butterflies) if the caster failed his Spellcraft roll (for 3.5, Concentration usually represents "did I cast the spell right?", while Spellcraft is "what do I know about magic in general?", and Caster Level is "how good am I at using magic?" Whichever skill it is, I'll refer to it as "casting roll" for now). You use the benign mishap-table if the spellcasting-roll fails in a low-stress situation, or if a lower-level spell failed (levels 1-3, probably), or when the caster casts one too many times in a row (or the casting-check just increases).

Then, you make a similar "dangerous" mishap table, for when the caster fails casting a 4-6th level spell, or when the casting roll fails in a high-stress situation like combat, or if the caster casts far too many times in a row. This one is why you don't try magic at home; uncontrolled explosions of pure magic (a few d6s of damage to everyone in 20ft?), summoning random Fiendish critters who get a roll to determine if they're hostile or indifferent, Dimension-Dooring you in a random direction, 40ft radius save vs. deafened for a few minutes, setting a nearby object (or yourself) on fire. Things like that.

Lastly, you'd prepare the "Oh ****" table, full of things like summoning demons and massive explosions, which could probably turn a battle around. You only bring out this table out when you fail a high-level spell under pressure. Critters summoned would be stronger (possibly with one of the Pseudonatural or Half-Farspawn templates for flavor), Fireballing a randomly-determined target within 100ft, turning you orange for a week, being possessed for a few rounds or minutes (with a save, of course. Even if you make it, you know a demon was trying to hijack your brain), or similar huge annoyances.

Maybe you'd have an additional "Apocalyptic" table, reserved only for truly epic magic-fails (9th level spells? Epic spells? I don't know). That would include things like ripping open permanent portals to hell, being possessed for a few days, transporting everyone in a radius to a randomly-determined plane, shutting down the caster's magic for a while, and so on.


All the negative effects should scale with caster level, so they remain dangerous at all levels, even if the character becomes good enough at Casting-Rolls that they rarely fail. You'd also want to find some way of ensuring that the failure chance is rarely zero, like natural 1s being automatic failures in combat.

[Mnemnosyne]

I don't like any suggestions that throw randomness into the mix on a regular basis. Randomness is fine on a limited scale, like in a wild magic zone, but if it's everywhere, it's a problem, because then magic becomes unreliable. Magic is the spellcaster's main method of interfacing with the world. And it comes at a limited number of uses per day. It shouldn't be unreliable. When you cast a spell, you should be confident that at the very least, the enemy will have to make a saving throw or you'll have to try to overcome SR. If magic was infinite per day like melee attacks or maneuvers, sure. A chance each time to not do anything at all is reasonable (although note that in all those cases, the chance is still generally based on the enemy's defenses).

Making magic less reliable actually encourages spellcasters to find the most absolutely overpowered spells and memorize as many copies of them as possible. Because they never know when one of those copies will fail, or just backfire. So they can't take the risk of memorizing anything but the most versatile, effective spells ever, and as many times as possible. It encourages as many shenanigans as possible to get as much effectiveness as possible out of your magic, because you never know when it's going to fail on you, so you need backups for your backups.

The fatigue system I mentioned from Player's Option: Spells and Magic doesn't have randomness (except the saving throw when you hit mortal fatigue). You know at the time you cast a spell exactly how much it's going to fatigue you and what fatigue level that's going to set you at. You can make informed, tactical decisions about your magic use. It gives you consequences you can plan on and take into account when making decisions, and these are very important things to be able to count on.

[Tyndmyr]

So... "magic is dangerous" is actually a very common trope in most of fantasy, and I feel D&D doesn't actually emulate that well. Of course, there are cursed items and monsters created by accident, but the players don't really experience the "dangerous" part of casting spells. If you wanted to simulate consequences for magic, what would you do, both mechanically and fluffwise?

Not play D&D.

[Psyren]

Critical failures on concentration checks, resulting not in spell failure but in the spell having detrimental results. A fireball would go off in the caster's face, mirror image would affect an opponent, magic missile would target allies, and so on.

This will either not happen often enough to have any effect at all, or happen so often that you may as well ban casters, with little to no middle ground.



Accelerated aging. Every time a spell is used, the caster ages spell-level weeks. Eventually, they will start to hit age-related stat penalties.

All your casters are now Elves.



Magic attracts monsters and demons, who might hound or even attack the caster. Not so easy to cast in combat when the quasit who's been following you gives you a wedgie. And hard to justify using a high-level spell in combat when it might attract an arcane elemental who will drag you off to the elemental plane of magic forever.

At low levels, this will result in a bit of annoyance/comedy but little else. At high levels this is again a ban on casters since they can't use their best techniques without risking retirement.

[Tyndmyr]

Critical failures on concentration checks, resulting not in spell failure but in the spell having detrimental results. A fireball would go off in the caster's face, mirror image would affect an opponent, magic missile would target allies, and so on.

This is only relevant to low level chars. Also, skill boosting is trivial, resulting in a "you must be this cheesy to ride" effect. It means that moderate, non-munchkiny wizards are spectacularly ineffective, and a danger to their party.

And munchkiny wizards are not penalized at all.

Thus, you have encouraged the problem sort, and discouraged the good sort.


Accelerated aging. Every time a spell is used, the caster ages spell-level weeks. Eventually, they will start to hit age-related stat penalties.

Not relevant. There are many ways to circumvent aging, most of which are magic. Additionally, age related stat penalties are to physical attributes. Mental attributes get better. So really, this "penalty" is "cast too much, and you get better at casting!"


Magic attracts monsters and demons, who might hound or even attack the caster. Not so easy to cast in combat when the quasit who's been following you gives you a wedgie. And hard to justify using a high-level spell in combat when it might attract an arcane elemental who will drag you off to the elemental plane of magic forever.

This is another "you must be this cheesy to ride" effect. This is only a concern for non-optimizers. For the optimizers, this is known as "Woohoo, extra xp".

As a rough bar for considering moderate-high optimization, I give you my current char (http://www.myth-weavers.com/sheetview.php?sheetid=428296). If I gleefully ignore your penalty, or it provides a net bonus to me, while punishing a level 1 generalist wizard with average stats....it's a bad system.

This discards about 99% of "spellcasting consequences" systems.

[Gamer Girl]

Can we also come up with something along the lines of making spells not so 100% reliable (barring SR and passed saves)? Gamer Girl, like your #2 and 3 points. Care to elaborate?:smallbiggrin:

Sure.

1.Heavy Magic Use Lots of powerful magic use in a single area can cause weird effects. I generally use 100 spell levels in a turn for a base, but lots of places have a lower tolerance. The most common effects are dead magic, empowered magic or wild magic.

One big one to watch out for is too much conjuration magic can open a rouge portal.

2.Magic Leaks Much like water(though really more like radiation) magic will leak from any active source. A continual torch on a stone in the woods will leak out Transmutation Fire magic over the years, so near by flowers glow with continual fire, fireflies can burn and such.

This also go for personal magic. The base limit here is 25 spell levels, and after that they will leak and mix together. This can be avoided by mixing the right spells that complement each other, or by making new spells. Race also has an effect here as does the type of magic. For example, 'racial magic' does not count towards the limit. And spells that work good together, like mage armor and shield, but get their levels halved.

3.Beware the TargetNot everyone is the same. Woe to the human spellcaster that reads a demons mind. The raw chaos of the demons thoughs can effect and even hurt a human. The same goes for stealing the life force of anything not 'normally alive'(animals, humanoids, etc). Taking the life force of a pixie can have effects.

4.Unintended Effects 3X is very, very, very 'Rated Y' for spell effects. The things like 'oh all your clothing grows and shrinks with you' is bad enough, but most spells are 100% safe. Take water breathing, cast the spell and jump into a lake and kill, loot, repeat. That's boring. It can be more fun for the spell to grow the person some gills or a blow hole. I don't change the 'base spell', but i add 1001 variants. The pure elven version of water breathing polymorpths a land elf into a sea elf, for example(kind more like improved alter self).

Spells can linger even after the duration, if used too much or other strange effects happen. Use darkvision too much and your eyes might glow in the dark, for example.

I don't want to just kill off the character(''oh your spell went wrong you die, time for you to go home'') and don't want to make it useless(''Oh your spell goes wrong and your fingernails turn blue for a minute''). I want everything right in the middle, so it has impact, but often not fatal impact, but noticeable and maybe beneficial. So in general, this works with more role-players who have fun just playing the game, and not the kill-loot-repeat zombies.
Say Renelle drains the life from a pixie, this has the effect of shrinking her one foot in height(like reduce person). This is both a good and bad effect. She might be too small to weld her large weapon, but she might be small enough to slip through a cell bar.

Most of the effects are obvious to players who have real life intelligences above 8. If you steal some hit points from an Azer you will get burned. A five year old can understand that. So smart players just add it into another level to the game. But the danger is always there. You can steal a little life force from a nixie and get a great 'Missy the Missile'(watching the Olympics, right?) body, but too much will turn you into a fish!

Now my way is not for all players. I've had tons of players toss up their character and walk out of the game as 'Bull Strength caused two horns to grow out of your head and give you a -1 to charisma' and they whined and cried that their super cool uber sorcerer build was ruined by only having a +19 and not a +20 for all charisma effects. Or the ''oh no my character has gills? I demand we stop the game right now and my character walks the couple of days back to town and finds a guy and cures him and then we continue the adventure'' types don't do well in my games.

[NichG]

There have been a number of threads like this in the past few weeks, with a lot of back and forth. I think my synthesis from it is that a price is better than a random gotcha psychologically and to control usage of the abilities. A random gotcha either paralyzes people, drives them away, or people ignore it and blast on. A price means people adjust their actions to keep the price payable.

That said, a price doesn't make magic mysterious, it just gives it consequences. So if mystery is the goal, you need to go in a slightly different tack.

My suggestion for mysterious magic is, bring back nontrivial interactions. It used to be that Fireball wouldn't work on the Plane of Water, Divination spells would return manipulative answers on Carceri (and would require a sacrifice to work at all), Conjuration spells on Acheron would cause the caster to trade places with the summoned creature rather than just bringing them in, and so on. Based on where you used magic, it might bite you, but it'd always bite you in the same ways once you learned the rules (or asked ahead and found out about them in advance). Sometimes you could figure them out, sometimes not.

This is fine for planar ventures, but it still leaves magic on the prime as reliable, repeatable, and perfectly understood by its practitioners. My suggestion there would be to create a list of 'dominant effects'. For instance, certain modifications that happen when 'Fire is Dominant', other modifications happen when 'Evil is Dominant', etc. Apply these dominant zones liberally throughout the world in any interesting places. Give players the ability to determine what is dominant. Turn it into a puzzle, a mystery that can actually be unraveled rather than just being arbitrarily random.

Ex:

Fire Dominant: Spells that create liquids instead create clouds of the liquid - Melf's Acid Arrow becomes a line of acidic fog, etc. Divinations work better if fire is used as a focus for the divination, otherwise flames are sometimes seen to obscure part of the image or information whenver divination is performed on things within. Fire spells are enhanced, causing the environment to catch fire in a way that burns without fuel, not damaging the environment but persisting until extinguished. Spells with the [Cold] descriptor are completely suppressed and do not function within.

Madness Dominant: Divination spells return random information, oddly pertinent to the caster but of dubious truth. Furthermore, these delusions can be real to the caster, both positively and negatively. See Invisibility reveals people that aren't there, who might injure the caster with their attacks or perform a helpful service for the caster with real, physical consequences. Illusion spells are self-willed, but still immaterial.

Peace Dominant: Spells cast in this region have their damage downgraded by one type from awful/permanent stuff towards less harmful types. Vile/frostburn/whatnot becomes lethal, lethal becomes nonlethal. Drain becomes damage. Summoned creatures generally will disobey commands to initiate violence.

Power Infused: All spells are increased in radius of effect by 100%, and spells slots that were left empty (but not used up) by people entering the area are filled with a random spell effect of the appropriate level at the rate of one spell level per minute. This can be used to perform spell research, but for these unstable effects one is never sure what it does without casting it.

Time Dominant: All spell effects enter into existance anything from one round before to one round after they are cast, randomly. Someone causing a paradox by not casting future-spells gathers a point of Alternity to themselves - Alternity decreases at a rate of one point per minute, but each point of Alternity held makes the caster's spell effects 10% less real. Ostensibly very high levels of Alternity make the caster's spells more real to somewhen else, which could have unpredictable effects (Alternity ratings of 8+ are 'interesting' in this way)

And so on... Also, these are things where the players themselves should not know the details of these things beforehand, only the idea that these interactions do exist. A reasonable Knowledge check could reveal some of the details (maybe base DC 20, an additional effect or detail for every 5 they beat the DC by).

[Wise Green Bean]

I like rocking it Cthulhu style. Magic is an otherworldly force beyond human comprehension. Have it slowly chip away at sanity!

Massive amounts of lethal damage is not the answer. Maybe nonlethal with smaller portions could work(like BoED's Word of Power feat). Take a d4/spell level. Doesn't make magic useless, but they are gonna be keeping it to a minimum each encounter and will probably have to whip out a crossbow after a grease and a haste. And if they are unlucky, they pass out, and take no further part in the encounter. Less dramatic than the Russian Roulette thing, and you still run into problems with the really big stuff, but the solution with the absurd stuff honestly is banning it. Lighting the house on fire is one thing, blowing up everything in a hundred miles is another.

[Fable Wright]

...Just going to leave this SRD Sanity variant (http://www.d20srd.org/srd/variant/campaigns/sanity.htm) here, what with the table of how much sanity casting a spell takes away and the consequences...

[Doxkid]

A scaling penalty or detrimental effect that only affects the highest spells the caster can cast.

[Arbane]

Important question that needs to be asked with some of these systems: How possible is it for an apprentice to get to level 1 (or level 1-3 or whatever) without dying or becoming unplayable?

Systems I've seen:

Shadowrun has Drain: Cast a spell under your limit, you need to roll to avoid stun damage (fatigue) over your limit, you're rolling to avoid lethal damage.
Call of Cthulhu has sanity loss. That's what you get for messing with incomprehensible alien superscience, monkeyboy!
Unknown Armies has Obsessions: To be a magician, you have to be insane to START with. And gaining magic 'charges' can be inconvenient, dangerous, immoral, or illegal, depending on what your obsession is.

Systems I've heard about:
ISTR the Black Company d20 game had some rules for magic backlash, but I remember someone commenting that it seems to be mostly a system for punishing anyone for being hubristic enough to try to be a spellcaster below level 20. (And that's not a moot point - one of the NPCs is level 40-something.)
The Conan d20 game has Corruption rules, but I don't know how good they are.