Short guide to forcing concentration checks and other mean caster blockers

[Aharon]

3.5 is the caster edition, no questions asked. There are few ways to shut down casters. However, they do exist, and if they are used, can make the caster's life at least a little harder. So, without further introduction, my compilation of ways to do that. I only used the PHB and the SpC, I would welcome additions fromm other sources. To nobody's surprise, a lot of the anti-caster solutions are itself only available to other casters...

Force Concentration Checks

Damage during spell: Ready Attacks/damaging spells, condition „Enemy casts a spell“
Entangle:

PHB: Entangle, Animate Plants, Animate Rope, Snare, Web, SPC: Avascular Mass, Band of Steel, Entangling Staff, Orb of Electricity, Shadow Binding, Shadow Landscape, Net, Tanglefoot Bag,
Counters: Short Distance Transport (Baleful Transposition, Dimension Door, Knight’s Move, Translocation Trick, G’elsewherechant etc.), Freedom, Freedom of Movement, Ruby Ray of Reversal, Lesser Globe of Invulnerability, Globe of Invulnerability, Spell Immunity


Grapple/Pin:

PHB: Bigby’s Crushing Hand, Bigby’s Grasping Hand, Evard’s Black Tentacles, Telekinesis, SPC: Earthen Grasp, Entangling Staff, Hungry Gizzard, Ice Claw, Kelpstrand, Shadowy Grappler, Spiritjaws,
Counters: Short Distance Transport (Baleful Transposition, Dimension Door, Knight’s Move, Translocation Trick, G’elsewherechant etc.), Freedom, Freedom of Movement, Ruby Ray of Reversal


Continous damage:

PHB: Incendiary Cloud, Melf’s Acid Arrow, Acid Fog, Chill Metal, Heat Metal, Creeping Doom, Insect Plague, Summon Swarm, SpC: Bone Fiddle, Heartfire, Clutch of Orcus, Negative Energy Aura, Thunderhead, Creeping Cold, Decomposition, Winter’s Embrace, Vortex of Teeth, Freeze, Inferno, Belker Claws, Burning Blood, Vitriolic Sphere, Firebrand, Shroud of Flame, Flensing, Freezing Fog, Malevolent Miasma,


Distracting Spell:

PHB: Dancing Lights, Ghost Sound, Lullaby, Silent Image, Unseen Servant, Ventriloquism, Minor Image, Pyrotechnics, Whispering Wind, Major Image, Sculpt Sound, Persistent Image, Permanent Image, Programmed Image
SpC: Ghostharp, Songbird, Amplify, Distract, buzzing bee, Creaking Cacophony, Dirge of Discord, Dissonant Chant, Distracting Ray,


Weather caused by spell:

PHB: Obscuring Mist, Fog Cloud, Acid Fog, Solid Fog, Mind Fog, Control Weather, Control Winds, Gust of Wind, Whirlwind, Whispering Wind, Wind Wall, Incendiary Cloud, Stinking Cloud, Cloudkill, Storm of Vengeance, Ice Storm, Sleet Storm,
SpC: Contagious Fog, Freezing Fog, Magic Miasma, Malevolent Miasma, Acid Storm, Blood Sirocco, cloud of Bewilderment, Cloudburst, Inky Cloud, Murderous Mist, Storm of Elemental Fury, Breath of the Jungle, Doomtide, Cyclonic Blast, Eye of the Hurricane, Reality Maelstrom, Stormtower, Greater Whirlwind, Acid Storm, Anarchic Storm, Axiomatic Storm, Holy Storm, Unholy Storm



Now why go through all this? After all, a few ranks in concentration obviate all these dangers?

Partly, that's true. Caster's can cast their lower level spells with little chance of failure. However, the DCs are scaling with the spell level. If I want to get my highest level spell out, failure chances look like this (assuming Con 16, full ranks in Concentration, +Con Item at 7th, 12th and 14th level. The magic missile is cast by a caster 5 levels lower, max 9th level):



Level
mod
Entangled
Fail
Grappled
Fail
Magic Missile

Fail

171640%2165%1430%
281635%2160%1425%
391735%2260%1525%
4101730%2255%1520%
5111830%2355%1620%
6121825%2350%1615%
7141920%2445%1710%
8151915%2440%2125%
9162015%2540%2225%
10172010%2535%2640%
11182110%2635%2740%
1220210%2625%3045%
13212725%3145%
14232715%3555%
15242815%3655%
16252810%3650%
17262910%3750%
1827295%3745%
1928305%3740%
2029300%3735%


So I can either choose to cast a lower level spell with higher chance of success - or I can risk using one of my highest level spells with a sometimes significant chance of failure. In both cases, the result is less power for my caster...

As promised in the title, there are a few other solutions - I didn't go through all the spells here, there are many, many spells that cause these conditions.



Against spells with verbal Components:

Deafened, Silenced




Against targeted spells:

Blindness




Against spells with material components/focus

Sunder held material component/focus



A lot of status effects (like nauseated, caused by Stinking Cloud) also inhibit casting. This leads back to Battlefield control in general often being a very useful option :smallbiggrin:

Feats:
Magic Disruption for making enemies' spells slightly worse, Mage Slayer line.

Counterspelling aided by:


Divine Defiance (FCII), immediate action counterspell by spending rebuke undead attempts
Battlemagic Perception (HoB), counterspell without line of sight
Arcane Spellsurge - use standard action to ready counterspell


I'm looking for constructive criticism and would love it if other people saw this as a useful research and would add spells/tricks from other sources.

Edited to add ideas by posters. Thank you, Oldtrees1 for discussion of Concentration DCs and formatting, and denthor, Zaq and Âmesang for pointing out additional ressources!

[Zaq]

Complete Mage has the Magic Disruption reserve feat, but it's pretty weaksauce, so I don't think it's generally a good idea to use it.

Unboosted counterspelling is typically a waste of time, but there are ways to make counterspelling less action-heavy, in which case it can be a valuable resource (even though we're still in casters-fighting-casters territory). The feat Divine Defiance (FCII) is a good start, and the spell Battlemagic Perception (HoB) is also useful.

For non-casters, the Mage Slayer line of feats (Complete Arcane) has some downsides, but it's better than nothing if you can get into melee range with a caster in the first place.

[Âmesang]

I know it's not the typical use, but the thought came to mind of using arcane spellsurge to cast standard action spells as swift actions and then using your normal standard action to ready an action for counterspelling.

[OldTrees1]

It is Continuous damage during the action so for many spells the damage does not manage to happen at the right time.

Also remember that the DC is important. Most of the effects listed in the OP are for the static DC 5 thru DC 20 checks. The scaling DCs are:
10+Damage dealt
10+0.5*continuous damage (remember damage needs to happen during the action)
DC of the distracting spell (even if it does not normally have a DC) unless the distraction is covered by one of the static DCs

[Aharon]

Thank you, OldTrees1!


It is Continuous damage during the action so for many spells the damage does not manage to happen at the right time.

Also remember that the DC is important. Most of the effects listed in the OP are for the static DC 5 thru DC 20 checks. The scaling DCs are:
10+Damage dealt
10+0.5*continuous damage (remember damage needs to happen during the action)
DC of the distracting spell (even if it does not normally have a DC) unless the distraction is covered by one of the static DCs

@continous damage during the action:
The example spell given in the PHB for that kind of spell, Acid Arrow (http://www.d20srd.org/srd/spells/acidArrow.htm), deals damage in more than one round. I assume that continous damage means damage taken from one source over more than one round - given the discrete nature of events in DnD, how else would you define continous?

@DCs:
The DCs are as follows:


Damage during spell: DC 10+Damage taken+spell level
Entangle: DC 15+spell level
Grapple/Pin: DC 20+spell level
Continous damage: DC 10+1/2 damage+spell level
Distracting Spell: DC (DC of distracting spell)+spell level
Weather caused by spell: DC (DC of spell causing weather)

[Eldariel]

Continuous damage is any DoT-effect that's still affecting the character. Rules Compendium stipulates that "If the last damage dealt was the final damage that the effect could deal, then the damage is over and can’t distract you." - thus, if the effect no longer affects you at the moment of casting, you don't have to roll Concentration. While the damage occurs at the beginning of the turn, that's just a simplification of the damage being constant.

I'd say any area spells (Maw of Chaos, Acid Fog, etc.) as well as similar effects (lava, being on fire, acid rain, hurricane, etc.) would count in addition to multiturn spells like Creeping Cold, Acid Arrow, etc. Note, some of those effects require Concentration-checks to cast in anyways; I'd ask for two. However, if you leave the area effect during your turn before casting, you wouldn't have to roll.

However, RC also states that "Repeated damage isn’t the same as and doesn’t count as continuous damage." - it's a viable interpretation to state that e.g. lava immersion amounts to repeated damage. I'd rather interpret it as referring to stuff like Black Tentacles, attacks, etc. hitting multiple turns in a row though.

[OldTrees1]

Thank you, OldTrees1!



@continous damage during the action:
The example spell given in the PHB for that kind of spell, Acid Arrow (http://www.d20srd.org/srd/spells/acidArrow.htm), deals damage in more than one round. I assume that continous damage means damage taken from one source over more than one round - given the discrete nature of events in DnD, how else would you define continous?

@DCs:
The DCs are as follows:


Damage during spell: DC 10+Damage taken+spell level
Entangle: DC 15+spell level
Grapple/Pin: DC 20+spell level
Continous damage: DC 10+1/2 damage+spell level
Distracting Spell: DC (DC of distracting spell)+spell level
Weather caused by spell: DC (DC of spell causing weather)

In reverse order:
@DCs
Thanks for catching "+ the spell level of the spell the caster is casting". Although the majority of my point there was that some of the DCs did not scale with the disruptor (but that 3 of them did scale with the disruptor). This matters because the caster can accommodate with skill ranks for the static and their scaling (so anything that scales with the disruptor is going to be better bets for disrupting).

PS: You left out "DC 5+spell level for a high wind carrying blinding rain or sleet" and both DC "10+spell level" that I can see on the SRD. I assume you omitted them because you don't have any examples of how to force those cases yet.

@Continuous
We agree about what effects count as continuous. I was just remarking on seeing the distraction listed in the SRD as "Taking continuous damage during the action". This might mean that it only applies to spells with long enough casting times that the damage from acid arrow would hit during the casting time. So being hit with acid arrow would not imped me from casting Fireball for example.

DM note: Honestly this seems like a mistake between RAI and RAW. I would have it be "Under an effect with continuous damage" to cover for how continuous damage is mechanically represented as discrete chunks with a duration.

[Aharon]

In reverse order:
@DCs
Thanks for catching "+ the spell level of the spell the caster is casting". Although the majority of my point there was that some of the DCs did not scale with the disruptor (but that 3 of them did scale with the disruptor). This matters because the caster can accommodate with skill ranks for the static and their scaling (so anything that scales with the disruptor is going to be better bets for disrupting).


Assuming starting Con of 16, full ranks, +con-items at 7th, 12th and 14th level (purchased for ~20% of WBL), the chances of succeeding at the highest level spell might look like this:



Level
Ranks+Con
DC for highest level
spell while entangled
Failure Chance
DC for highest level
spell while grappled
Failure Chance
DC for Damage by Magic Missile
@CL (Min(Max(Caster CL-5;1);9))
Failure Chance


1
7
16
40%
21
65%
14
30%


2
8
16
35%
21
60%
14
25%


3
9
17
35%
22
60%
15
25%


4
10
17
30%
22
55%
15
20%


5
11
18
30%
23
55%
16
20%


6
12
18
25%
23
50%
16
15%


7
14
19
20%
24
45%
17
10%


8
15
19
15%
24
40%
21
25%


9
16
20
15%
25
40%
22
25%


10
17
20
10%
25
35%
26
40%


11
18
21
10%
26
35%
27
40%


12
20
21
0%
26
25%
30
45%


13
21
22
0%
27
25%
31
45%


14
23


27
15%
35
55%


15
24


28
15%
36
55%


16
25


28
10%
36
50%


17
26


29
10%
37
50%


18
27


29
5%
37
45%


19
28


30
5%
37
40%


20
29


30
0%
37
35%



(if anybody knows how to make this table look nice in the forum editor, I'm all ears)

So there's a significant chance of losing high-level spells. The caster can either take the risk, or rely on lower level spells - making him automatically less of a threat.
The scaling is to his advantage, but it is still hurting him (I think).

[denthor]

You missed the one that always gets me stinking cloud forces a fort save bad for wizards you then must pick a direction blind if you still in the affected area another fort save. Still unable to see if you make it out you might unwittingly stumble into thief,fighter bad bad bad.

If you miss fort save and make it out you are coughing 1d4 +1 rounds how long is the wizard out of the fight?

[OldTrees1]

Assuming starting Con of 16, full ranks, +con-items at 7th, 12th and 14th level (purchased for ~20% of WBL), the chances of succeeding at the highest level spell might look like this:



Level
mod
Entangled
Fail
Grappled
Fail
Magic Missile

Fail

171640%2165%1430%
281635%2160%1425%
391735%2260%1525%
4101730%2255%1520%
5111830%2355%1620%
6121825%2350%1615%
7141920%2445%1710%
8151915%2440%2125%
9162015%2540%2225%
10172010%2535%2640%
11182110%2635%2740%
1220210%2625%3045%
13212725%3145%
14232715%3555%
15242815%3655%
16252810%3650%
17262910%3750%
1827295%3745%
1928305%3740%
2029300%3735%


(if anybody knows how to make this table look nice in the forum editor, I'm all ears)

So there's a significant chance of losing high-level spells. The caster can either take the risk, or rely on lower level spells - making him automatically less of a threat.
The scaling is to his advantage, but it is still hurting him (I think).

Fixed it!


Level
mod
Entangled
Fail
Grappled
Fail
Magic Missile

Fail

171640%2165%1430%
281635%2160%1425%
391735%2260%1525%
4101730%2255%1520%
5111830%2355%1620%
6121825%2350%1615%
7141920%2445%1710%
8151915%2440%2125%
9162015%2540%2225%
10172010%2535%2640%
11182110%2635%2740%
1220210%2625%3045%
13212725%3145%
14232715%3555%
15242815%3655%
16252810%3650%
17262910%3750%
1827295%3745%
1928305%3740%
2029300%3735%


The key things for the formatting were:
Spaces are counted. Do not put extra spaces inside one of the s
Class Grid gives it all those nice lines
Shorter titles look better for columns of small numbers
You don't need to align right/left/center each cell

[Aharon]

@Oldtrees1:
Big thank you for the formatting aid :-)


"Taking continuous damage during the action".

So basically, you would only allow that to apply to spells with 1 round or higher casting time? The pour spontaneous casters get worse at metamagic, and summoners are fighting tears ;-)

@Denthor:
added, thank you.

[OldTrees1]

@Oldtrees1:
Big thank you for the formatting aid :-)


So basically, you would only allow that to apply to spells with 1 round or higher casting time? The pour spontaneous casters get worse at metamagic, and summoners are fighting tears ;-)

You're welcome!

Yeah it looks like RAW they would only apply to those long casting times. However I think I would houserule it based upon the discrete damage simulating continuous damage.