Does anyone use the Massive Damage rules?

[PhantasyPen]

As the thread title says, I am just curious how many of you use the Massive Damage rules, (or even remember they exist). For those of you that use them, do you use them as-written, or have you modified them in some way?

[Venger]

Absolutely not. A minimally competent character should be able to deal 50 damage with every hit after very low levels. it would make the game even rocket taggier than it already is. it's a terrible variant.

[BowStreetRunner]

I've been in games where the Massive Damage (http://www.d20srd.org/srd/combat/injuryandDeath.htm#massiveDamage) rule came into play. We played it as-written. Usually it only really comes out at higher levels though.

EDIT: I should point out that we were very careful about distinct packets of damage. So that guy who hits you with a flaming sword that does 40 weapon damage plus 10 fire damage won't trigger this.

[Venger]

I've been in games where the Massive Damage (http://www.d20srd.org/srd/combat/injuryandDeath.htm#massiveDamage) rule came into play. We played it as-written. Usually it only really comes out at higher levels though.

EDIT: I should point out that we were very careful about distinct packets of damage. So that guy who hits you with a flaming sword that does 40 weapon damage plus 10 fire damage won't trigger this.

How often did pcs die from it?

That's interesting. I don't think that's how the rules work by default, but that's a good houserule to make it come up less often. Did you count precision damage separately as well?

[BowStreetRunner]

How often did pcs die from it?

That's interesting. I don't think that's how the rules work by default, but that's a good houserule to make it come up less often. Did you count precision damage separately as well?

Never had a PC die from it. By the time it comes into play any PC should be able to make a DC 15 Fortitude save. We did occasionally take down a monster with a lot of HP but low FORT save. Not very often though. The best way I've ever seen it used was by an attacker paired with a debuffer who was really, really good and making enemies miss their saves.

By default the rules state it has to be a single 'attack' that does the damage. So I guess hitting with Manyshot (one attack, multiple arrows) would still work. In that respect, I guess we weren't entirely using the rules as written. But treating each damage packet separately was something we used for lots of other reasons (like resolving DR) so it just came naturally. Precision damage generally increases the weapon damage, so that was not a distinct packet but just an adder.

[Falontani]

Please no. Just no. I don't understand why massive damage is a static 50.

[BowStreetRunner]

Please no. Just no. I don't understand why massive damage is a static 50.

If you tried to go with a percentage, like 75% of max hp, then doing 3hp to a level 1 wizard with 4hp would count. So I think they just couldn't find any other uncomplicated way to do it that wouldn't have really strange results. Sure, some characters have lots more hp, but the damage being done is still the same regardless of whether they can soak it all or not.

[Uncle Pine]

For me it's in the same bucket as multiclass xp penalties. In other words no, I've never EVER used it.

[Mike Miller]

When 3.5 was new, my group used it. We never saw any kills by it though. Basically what BowStreetRunner said.

[Venger]

Please no. Just no. I don't understand why massive damage is a static 50.
Because when they "playtested" the game, their druid never wildshaped, and flailed away at enemies with a scimitar doing 1d6+1. This is the baseline level of mental competency that went into optimization, so this what what they set their assumed power level for a theoretical players at. "50 damage? Gee, it'll take a party of 4 four whole rounds to do that. Only a big tough monster like a hulking corpse or a famine spirit could do all that damage at once!"

It would take a wizard casting fireball (basically the only method of hp damage inflicting they seem to know in core) until level 15 to deal this amount of damage on average.


When 3.5 was new, my group used it. We never saw any kills by it though. Basically what BowStreetRunner said.
This is very interesting. Do you guys have parties with low damage outputs?

[Kayblis]

It's a mechanic copied from other systems. It has a fixed 50 dmg threshold, but only forces a fixed DC 15 Fortitude save. In non-high-OP games, this means that the second it comes online, it's probably not enough to make a big difference. For a character to have significantly more than 50 HP and significantly lower than +15 Fort, you'd have to run either a caster or a big monster with low Fort. Of course, if you're playing with an ubercharger that kills everything by level 4, this rule might kill something that survived to 50 damage in a single blow - but that's not the usual.

Other d20 systems have more variable massive damage rules. Like, say, MD triggers at 20 damage or 1/2 max health, whichever is higher, and the Fort save is 5+(damage/2). If you fail, you're only unconscious. I've seen this is games with lower damages than 3.5 or PF.

[King of Nowhere]

No, it's just an extra bother. Plus it makes little sense to apply it statically to every monster.

Anyway, it would see use very rarely. At the level 50 damage per hit are a regular happenstance, you can divide the combatants in two categories: those that will fail a 15 fort check with a natural 1, and those who won't fail even then (I use the "natural 1 = -10" variant)

I also have to say, the later increases in level have come with a reduction of damage dealt. Oh, my players are fully capable of dealing 50 damage per hit to a lesser foe, but their foes right now are so stocked up with defences that little damage is actually dealt.

[Venger]

It's a mechanic copied from other systems. It has a fixed 50 dmg threshold, but only forces a fixed DC 15 Fortitude save. In non-high-OP games, this means that the second it comes online, it's probably not enough to make a big difference. For a character to have significantly more than 50 HP and significantly lower than +15 Fort, you'd have to run either a caster or a big monster with low Fort. Of course, if you're playing with an ubercharger that kills everything by level 4, this rule might kill something that survived to 50 damage in a single blow - but that's not the usual.

Other d20 systems have more variable massive damage rules. Like, say, MD triggers at 20 damage or 1/2 max health, whichever is higher, and the Fort save is 5+(damage/2). If you fail, you're only unconscious. I've seen this is games with lower damages than 3.5 or PF.

If you're playing a caster or skulk type, that save will still probably screw you even into mid-high levels. Lots of people like playing non-brutish characters. Monster HD scales much more quickly than the party's does. Even if a monster is of a type without good fort saves, they usually have a lot of con and tons of hd, so are unlikely to fail a dc15, unlike an equivalent pc.

[tyckspoon]

It would take a wizard casting fireball (basically the only method of hp damage inflicting they seem to know in core) until level 15 to deal this amount of damage on average.


Level 10 (an Empowered 10d6 Fireball deals, statistically speaking, 52.5 damage) or 11 (Level 6 spells means a possible Maximized Fireball for a guaranteed 60 damage.) Without metamagic you can't reliably do it with Fireball at all thanks to the 10d6 cap on its progression. In raw dice, yeah, it takes to CL 15 before you're throwing enough d6 to expect more than 50 points on an average roll. Note that this probably means a Rogue is expected to never trigger Massive Damage, and a Fighter-type is probably only going to do it with Core's only supported One Big Hit style, mounted charging.

[Venger]

Level 10 (an Empowered 10d6 Fireball deals, statistically speaking, 52.5 damage) or 11 (Level 6 spells means a possible Maximized Fireball for a guaranteed 60 damage.) Without metamagic you can't reliably do it with Fireball at all thanks to the 10d6 cap on its progression. In raw dice, yeah, it takes to CL 15 before you're throwing enough d6 to expect more than 50 points on an average roll. Note that this probably means a Rogue is expected to never trigger Massive Damage, and a Fighter-type is probably only going to do it with Core's only supported One Big Hit style, mounted charging.

Oh, absolutely if you're taking even a minimal effort in making your wizard playable, you can do it earlier. I was just taking a straight wizard with no searing spell or metamagic or anything that only casts fireball since that's how wotc thinks you play wizard

I stupidly remembered fireball's cap as being 15, but yeah, your math is right.

Yes, I definitely think that they expected rogue and fighter (and cleric because he just heals, of course) to trigger massive damage either

[Mechalich]

It's a mechanic copied from other systems.

It's actually an unmodified mechanic from earlier editions - death from massive damage triggered at 50 HP (and required a save vs. death) in that system. This is not the only such mechanic - falling damage was likewise pulled across the edition boundary without any change. Both rules ended up being absurd because of the vast difference in HP values between editions that the designers failed to understand in any functional way.

In 2e, 50 damage was a lot. A reasonable front-line fighter had 1d10 hp per level (plus a con bonus they might not have), and that capped at 9th level and was replaced by a flat 3 hp per level after level 9. So even a 15th level fighter might have only around 80 hp, and other party members much lower. A 20th level wizard with under 40 hp was perfectly reasonable. So in that edition, 50 damage was a reasonable benchmark to have players make an 'oh s***' role, in 3e it's not, but the fix is simple in terms of making the massive damage benchmark 100 or 150 damage. In the same sense falling damage should go up well past 20d6.

[Covenant12]

This rule goes in the same category as critical fumbles on a natural 1. Sounds interesting if you don't think to hard, but punishes players severely for no reason.

Unless you're playing Paranoia, not DnD. Then it sounds like a great rule.

[Mike Miller]

This is very interesting. Do you guys have parties with low damage outputs?

It wasn't due to low damage, but because the DC 15 FORT save was so easy by the time 50 damage is a more common occurrence. Also, I haven't used the variant for years.

[KillianHawkeye]

I use this rule in my games. It rarely comes up because my group aren't big optimizers and we don't play to very high levels, and when it does it usually doesn't trigger because the DC 15 Fort save is fairly trivial by then.

I certainly wouldn't compare it to multiclassing XP penalties or critical fumble house rules.

[martixy]

Sort of? Yes? No? Technically. Kinda.

I borrow heavily from Pathfinder(e.g. characters die at -Con score). PF's massive damage rules goes as follows:

If you ever sustain a single attack that deals an amount of damage equal to half your total hit points (minimum 50 points of damage) or more and it doesn’t kill you outright, you must make a DC 15 Fortitude save. If this saving throw fails, you die regardless of your current hit points. If you take half your total hit points or more in damage from multiple attacks, no one of which dealt more than half your total hit points (minimum 50), the massive damage rule does not apply.

Except the Fort save DC in my game is 10 + 1/10 damage suffered. So it starts at 15, but goes up. I also use called shots which play off of the rule, with their "debilitating" severity where you get to chop off limbs, squash heads like grapes and spill your opponent's guts on the ground.

So... technically kinda, because it's in the game, but we're at L5 right now and only just approaching 50s in the damages.

[gooddragon1]

Steadfast determination prevents auto failing fort saves on a 1. That would take care of it later on as well. If you're taking multiple instances of 50 damage in a fight you'll be having bigger things to worry about than fort saves.

Here, just made a homebrew feat for fun: Persistent Fortitude (http://www.giantitp.com/forums/showthread.php?559685-Persistent-Fortitude-(General-Feat)-no-death-from-massive-damage-other-benefits&p=23098368#post23098368).

[NamelessNPC]

We use, in PF, a modified rule. You have to check if the damage is both at least 50 and half of your total hp. It comes up very rarely

[BowStreetRunner]

This is very interesting. Do you guys have parties with low damage outputs?
I LOLed at this, because the vast majority of D&D players I've come to know within the past 30+ years don't optimize to the levels that are commonly described in this forum. In fact, I think a lot of the people in these forums don't optimize in real games to the level they say they do in their posts. :smallamused:

On the other hand, I still would like to try building a character optimized to take advantage of this rule. I mentioned earlier I saw a tag team that used it - one was a Hexblade build that could do a decent job of lowering an opponent's saves and the other was a 'big stick' character optimized around doing mega-damage.

I'm thinking Hexblade with Dark Companion and enough levels of Paladin of Tyranny to pick up Aura of Despair. High Intimidate to Demoralize opponents.

[Thurbane]

Yes, we do. It ended up in a spectacular one-shot kill on a red dragon while were were playing RHoD: the Warmage blasted it with an Empowered Orb of Cold, and it rolled a 2 on it's Fort save.

We also use favoured class XP penalties and track encumbrance.

I'm told we're quite weird. :smalltongue:

[Covenant12]

I LOLed at this, because the vast majority of D&D players I've come to know within the past 30+ years don't optimize to the levels that are commonly described in this forum. In fact, I think a lot of the people in these forums don't optimize in real games to the level they say they do in their posts. :smallamused:That goes double or triple for me. I enjoy optimizing, I have a natural passion and talent for math, though. The people I've played with, also over 30+ years, if they skimmed the spell descriptions and picked stuff that looked useful they'd be far above my average experience.

Since the boxed sets, my favorite build has been god wizard (since decades before I heard the term), but I've always pulled my punches. For 3.5, I have spells like black tentacles ready, but I usually cast enlarge person on the beatstick, greater invis on the rogue, or haste on the party. I like having the ability to overpower CR+2 opponents, but I try to make the party shine. I've seen the occasional very-high op campaign on the forums on occasion, but they're very rare. I suspect a lot on these forums are like me, either that or they get books chucked at them until they get banned from that DM's groups.

[Goaty14]

For me it's in the same bucket as multiclass xp penalties. In other words no, I've never EVER used it.

This. I even forgot it existed until you brought it up.

[Elkad]

Since the boxed sets, my favorite build has been god wizard (since decades before I heard the term), but I've always pulled my punches...

I'm much in the same boat. But I can't say "always". Very occasionally a DM annoys me enough and gets to "witness the power of this fully armed and operational battlestation". And then I apologize to the other players in the group and maybe reroll as a completely core Horizon Tripper or something.

[ZamielVanWeber]

Please no. Just no. I don't understand why massive damage is a static 50.

My DM houseruled it do 3x Con score and your HP goes to -1d10. I have had the only casualty of that -1d10 though. Needless to say, his replacement has a Con of 24 (and still nearly had to make the roll once). The save DC also scales based on damage that exceeds your threshold.

[Remuko]

I think I just used the D20 Modern version. Threshold was way lower, but i dont think failure was lethal for PCs so it wasnt that bad.

[BowStreetRunner]

I think I just used the D20 Modern version. Threshold was way lower, but i dont think failure was lethal for PCs so it wasnt that bad.
I've never seen this version before, but it looks interesting. Every character has a massive damage threshold equal to their CON, or if they have the Improved Threshold feat it becomes CON +3. Failing the DC 15 Fortitude save puts a character at -1 hp. Immunity to critical hits also gives immunity to massive damage.

I really imagine 'massive' damage begin a lot more than even most CON scores. Something more in the range of 3x CON score for most characters. The DC 15 Fort save becomes even more irrelevant to beefy characters, however. Since that is also based off of CON, characters with a high threshold also have a higher save.

[Telonius]

Used it during the first campaign we ever played; junked it after that.

We did use the "triple 20" houserule. If you roll a 20 on an attack, then roll another 20 to confirm the crit, roll again. If that result is also a 20, the target dies, no save. 1/8000 chance of happening. It came up exactly once, but was pretty spectacular when it did. Our sorcerer shot an Orb spell at a pyroclastic dragon, who "went up like the Death Star" according to the DM.

[PhantasyPen]

Used it during the first campaign we ever played; junked it after that.

We did use the "triple 20" houserule. If you roll a 20 on an attack, then roll another 20 to confirm the crit, roll again. If that result is also a 20, the target dies, no save. 1/8000 chance of happening. It came up exactly once, but was pretty spectacular when it did. Our sorcerer shot an Orb spell at a pyroclastic dragon, who "went up like the Death Star" according to the DM.

My old group used this rule too, it was pretty funny when I almost killed his final boss at level one when my monk rolled 20/20/18 on the dice for an Overpowering Attack.

[Blu]

Just to add a little to this discussion, 50 damage is not that far away actually. It's not a mid-level thing and even on low optimazitions it can came up pretty early.
Just by using Blade of Blood and Enlarge person i had a characer deal 36 damage on an attack at level 3 with a Greatsword. Even tough i did roll well on damage(a bit above average on each dice) i would say it is that close of a margin and i reckon that by level 5 i would probably have a damage that can average pretty close to 50.
Even worse, the attack that caused 36 damage wasn't even a crit.
50 damage can be an occurence even in low levels when a Fort 15 is not laughable yet so it goes to show how horrible the rule is.

[Zaq]

Just to add a little to this discussion, 50 damage is not that far away actually. It's not a mid-level thing and even on low optimazitions it can came up pretty early.
Just by using Blade of Blood and Enlarge person i had a characer deal 36 damage on an attack at level 3 with a Greatsword. Even tough i did roll well on damage(a bit above average on each dice) i would say it is that close of a margin and i reckon that by level 5 i would probably have a damage that can average pretty close to 50.
Even worse, the attack that caused 36 damage wasn't even a crit.
50 damage can be an occurence even in low levels when a Fort 15 is not laughable yet so it goes to show how horrible the rule is.

Devil’s advocate here: if it actually happens at low levels when 50 HP is a significant chunk of your max and a DC 15 Fort save isn’t trivial, that’s likely when the rule is INTENDED to be most relevant, because 50 HP all in one lump really IS kind of massive damage at that level.

The problem basically comes from the fact that it doesn’t scale at all in either direction, so at high levels it bogs down play with a ton of extra rolls that you’re unlikely to fail but that can technically kill you, resulting in fun for, well, very few playstyles.

My group has name-dropped the rule a few times, but I don’t think we’ve ever actually used it. I’m in favor of ignoring it; if 50 HP (or the threshold you set) really is massive damage, then you don’t need to reward the attacker or punish the target more than is already happening. If the threshold ISN’T actually massive damage to you, then acting like it is and tacking on a semi-gratuitous save-or-die effect (n.b.: I consider SoD effects to be some of the worst parts of 3.5’s design) is either pointless or vindictive.

[Kelb_Panthera]

Just to add a little to this discussion, 50 damage is not that far away actually. It's not a mid-level thing and even on low optimazitions it can came up pretty early.
Just by using Blade of Blood and Enlarge person i had a characer deal 36 damage on an attack at level 3 with a Greatsword. Even tough i did roll well on damage(a bit above average on each dice) i would say it is that close of a margin and i reckon that by level 5 i would probably have a damage that can average pretty close to 50.
Even worse, the attack that caused 36 damage wasn't even a crit.
50 damage can be an occurence even in low levels when a Fort 15 is not laughable yet so it goes to show how horrible the rule is.

If I'm guessing accurately at how this went down, even a crit would average just below the threshold in that setup unless you're power attacking. I'm also not seeing where 2 more levels would make the difference of ~20ish points of damage at those levels. Finally, what did you even hit that it wouldn't be killed outright by 50 damage at level 3?

What I'm getting at its that you've described here something that, to me at least, throws up a couple of flags that say "this is not a typical game; heavy op and encounters way above CR."

[Blu]

If I'm guessing accurately at how this went down, even a crit would average just below the threshold in that setup unless you're power attacking. I'm also not seeing where 2 more levels would make the difference of ~20ish points of damage at those levels. Finally, what did you even hit that it wouldn't be killed outright by 50 damage at level 3?

What I'm getting at its that you've described here something that, to me at least, throws up a couple of flags that say "this is not a typical game; heavy op and encounters way above CR."

Just to elaborate, said character was a Duskblade 2/Wizard 1. My first round in the combat was used to buff me with Enlarge person and to move on position and the second round was used to use Blade of blood while attacking with a now Large Greatsword.
For damage it was 3d6 from the greatsword, 3d6 from the blade of blood plus 4(1.5 x STR) plus 3(Knowledge devotion).
The combat was against a group of hobgoblins and i one-shot the leader. The DM was surprised with the damage.

2 more levels would mean a whole new spell level for me, with at least two spells that can increase that damage(that i remember on top of my head). Probably it would still need to be above average damage to get the 50 points. Unless i crit, then It would be easy to get average damage 50.

I honestly don't consider using one buff and one swift action spell to be heavy OP.

[Kelb_Panthera]

Just to elaborate, said character was a Duskblade 2/Wizard 1. My first round in the combat was used to buff me with Enlarge person and to move on position and the second round was used to use Blade of blood while attacking with a now Large Greatsword.
For damage it was 3d6 from the greatsword, 3d6 from the blade of blood plus 4(1.5 x STR) plus 3(Knowledge devotion).
The combat was against a group of hobgoblins and i one-shot the leader. The DM was surprised with the damage.

2 more levels would mean a whole new spell level for me, with at least two spells that can increase that damage(that i remember on top of my head). Probably it would still need to be above average damage to get the 50 points. Unless i crit, then It would be easy to get average damage 50.

I honestly don't consider using one buff and one swift action spell to be heavy OP.

I'm thinking bull's strength for one but blanking on the other.

To be clear, after ceding the advantage of going first or giving the enemy an extra action you did enough damage to OHKO a leader in a multi-enemy encounter with -long- odds of triggering MD that wouldn't have mattered anyway.

I'm not seeing the problem. I think you're overestimating how rapidly damage grows here. Even arcane channeling says hit -then- spell effect rather than being simultaneous.

Ultimately, MD only matters if the enemy has at least 51 hp in the first place.

I'll admit I was completely wrong about how you got there though. Assumed non-caster instead of Gish for some reason.

[Remuko]

I've never seen this version before, but it looks interesting. Every character has a massive damage threshold equal to their CON, or if they have the Improved Threshold feat it becomes CON +3. Failing the DC 15 Fortitude save puts a character at -1 hp. Immunity to critical hits also gives immunity to massive damage.

I really imagine 'massive' damage begin a lot more than even most CON scores. Something more in the range of 3x CON score for most characters. The DC 15 Fort save becomes even more irrelevant to beefy characters, however. Since that is also based off of CON, characters with a high threshold also have a higher save.

Yeah it works really well in modern since damage numbers arent as high and really dont scale (cuz guns) but it works okayish in D&D as well, as by the time things consistently hit over it, most characters can make the check somewhat reliably, and even a fail isnt insta death so its not TOO punishing (imo at least).

[Blu]

I'm not seeing the problem. I think you're overestimating how rapidly damage grows here. Even arcane channeling says hit -then- spell effect rather than being simultaneous.

Ultimately, MD only matters if the enemy has at least 51 hp in the first place.

I'll admit I was completely wrong about how you got there though. Assumed non-caster instead of Gish for some reason.

More on the idea of using spells that increase my damage on attacks. There is some spells in Spell Compendium that add one or two d6's to your attacks, some of wich also add more damage on crits.
Bull's strenght would also be a good one since then my damage from STR would bump from +4 to +7.

I may be overestimating it a little but it's not like something that only comes up by mid-levels. And has Zaq has said it, that amount of damage in itself is already it's pretty punishing to the defender it's not needed to just add a flat "roll or die" in it.

[D+1]

I used to think it was a good idea. Now I think it's just a sign of twisted expectations. If 50 points of raw damage needs to be one-shotting opponents then the hit points of those opponents should simply cease to increase above 50 hit points so that such an attack accomplishes that with raw damage alone. If you want hit points to increase above 50 then you are by definition accepting that a single 50-point attack is NOT sufficient to kill something and you similarly by definition should not need or want any additional rule to say that it will, and a save-or-die effect should not be proc'ed by a damage threshold alone.

[BowStreetRunner]

The more I think about it, the more this rule feels like something that could be relegated to a feat or special ability. A PC could create a build around it or a DM could build an encounter around it, but it wouldn't come into play otherwise.

[Kelb_Panthera]

More on the idea of using spells that increase my damage on attacks. There is some spells in Spell Compendium that add one or two d6's to your attacks, some of wich also add more damage on crits.
Bull's strenght would also be a good one since then my damage from STR would bump from +4 to +7.

So three rounds of buffing before the murder-smiting starts, 2 with a quicken rod you can't aford before mid~ish levels? Yeah, still okay with that and still only a mild chance of MD triggering outside of a crit. I generally consider 7 to be the start of mid-level.


I may be overestimating it a little but it's not like something that only comes up by mid-levels. And has Zaq has said it, that amount of damage in itself is already it's pretty punishing to the defender it's not needed to just add a flat "roll or die" in it.

I'm not saying it's an unqualified positive but the element of chance can have a useful place by the time it can be triggered reliably (barring ridiculous charger builds, of course.)

[HighWater]

If you tried to go with a percentage, like 75% of max hp, then doing 3hp to a level 1 wizard with 4hp would count. So I think they just couldn't find any other uncomplicated way to do it that wouldn't have really strange results. Sure, some characters have lots more hp, but the damage being done is still the same regardless of whether they can soak it all or not.
I'm not sure that 3 damage on a 1st level Wizard is NOT massive damage... Just because pretty much any melee has a good chance rolling that (or higher), doesn't mean it's not definitely massive for that Wizard. Obviously a Fortitude Save DC of 15 is unnecessarily steep at that level, but it could've quite easily been scaled.

Other than that, "Massive Damage" feels very weird considering Hitpoints supposedly "determine how hard your character is to kill" (PHB, p6). Got 500 HP? Well, I guess you're really hard to kill!... Except when you get hit for 50 damage 'cause you might just drop dead...

It also has some serious gameplay unfairness:
- It rewards THF, while it effectively tells TWF and sword&board to go take a hike. Too bad those are already the weaker melee styles. Although to be honest, at this point in designing the game, the designers probably had no idea of the power gap between them.
- It poses a much greater threat to melee (martials) than it does to ranged (casters): the melee get hit a lot more and therefore likely get hit for "Massive Damage" a lot more...
- It is unfavorable for PC's, like all "chancey" effects that go both ways...
- It is much less relevant to the Wizard than to the Barbarian: the Barbarian might actually have 50HP-and-then-some to tank a 50hp hit, only to possibly die of this fixed-limit feature. Meanwhile the Wizard will likely be too-dead-to-care-about-fortitude-saves when hit in the face for 50 damage...

[BowStreetRunner]

Other than that, "Massive Damage" feels very weird considering Hitpoints supposedly "determine how hard your character is to kill" (PHB, p6). Got 500 HP? Well, I guess you're really hard to kill!... Except when you get hit for 50 damage 'cause you might just drop dead...
I honestly always felt it was less intended for sword attacks and things like that and more for what to do when a wall falls on you. I remember a scene in a movie where they had one of those huge blocks that the great pyramids are made from held up by a huge crane and it fell on someone smashing them flat. I could see the conversation in development going something like this:

"Well, what if someone drops a wall on top of them?"
"I don't know, maybe say it's 50 damage. That should kill most characters."
"Dude, I think this game may reach a point where PCs have more than 50 hp."
"Really? Well, then let's just add a massive damage rule that anything over 50 hp also requires a Fortitude save."
"Okay. That will probably work."

[martixy]

The 3.5 rule is nonsensical. It really should scale.


The more I think about it, the more this rule feels like something that could be relegated to a feat or special ability. A PC could create a build around it or a DM could build an encounter around it, but it wouldn't come into play otherwise.

I agree with this. I introduced it as an element in my game. You can, if you want to, build a character around this concept. If you want your character to cause a bloodbath everywhere he goes...

It comes together in the following form:
I use PFs called shots variant rules. They have 3 stages of severity - normal, critical hits and debilitating blows(the latter one uses the same rule as massive damage and equals things like chopping off limbs, gutting people, etc).
Introduced a rule that says, certain damage types are favoured for certain called shots, which allows you to upgrade the "severity" of a called shot by 1 step for a small penalty to atk. It means you can cause the effects of a debilitating blow with a critical hit. Enter crit-fishing.
Vorpal weapons automatically increase the severity of a called shot by one step.
There's also a feat that allows you to total all damage from your attacks for the purpose of determining the severity of a called shot. Similar to the Clustered Shots (https://www.d20pfsrd.com/feats/combat-feats/clustered-shots-combat/) feat in PF(which incidentally is also useful, but for a ranged version of the build).