High CR traps

[Elder-Basilisk]

The traps in the 3.5 SRD only go up to CR 10. Is it just me or is it rather difficult to come up with good high CR traps? Most of them seem either rather deadly

For instance, Forcecage, Energy Drain, and Summon Monster VII trap: CR 12; magic device; touch trigger; automatic reset; multiple traps (one forcecage trap, one Energy Drain trap, and one summon monster VIII trap that summons a Celestial dire bear); spell effect (forcecage, 13th-level wizard), spell effect (energy drain, 17th level wizard, 2d4 negative levels for 24 hours, DC 23 Fortitude save negate), spell effect (summon monster VIII, 15th-level wizard, Celestial Dire Bear); Search DC 34; Disable Device DC 34

And that's a more reasonable one. This one, made by stringing together eight power word kill traps seems more than a little deadly.

Multiple Power Word Kill trap: CR 16; magic device; touch trigger; automatic reset; spell effects (Power Word Kill, 17th-level wizard); multiple targets (up to 8 creatures in the treasure room); Search DC 34; Disable Device DC 34

And, according to the rules, it would still be CR 16 if I replaced it with this:

Cone of Cold, Delayed Blast Fireball and Multiple Power Word Kill trap: CR 16; magic device; touch trigger; automatic reset; spell effects (Cone of Cold, 14d6 cold, reflex DC 17 for 1/2, 14th level wizard), (Delayed Blast Fireball 14d6 fire, reflex DC 20 for 1/2, 14th level wizard), (Power Word Kill, 17th-level wizard); multiple targets (up to 4 creatures in the treasure room); Search DC 34; Disable Device DC 34

Now a competent 14th level rogue (max ranks +17, int +2, heroism +2, masterwork theives tools +2) might be able to disarm it on a roll of 11 but it seems inordinately deadly for its CR even so.

Anything I'm missing here?

 

[Trainz]

And, according to the rules, it would still be CR 16 if I replaced it with this:

Cone of Cold, Delayed Blast Fireball and Multiple Power Word Kill trap: CR 16; magic device; touch trigger; automatic reset; spell effects (Cone of Cold, 14d6 cold, reflex DC 17 for 1/2, 14th level wizard), (Delayed Blast Fireball 14d6 fire, reflex DC 20 for 1/2, 14th level wizard), (Power Word Kill, 17th-level wizard); multiple targets (up to 4 creatures in the treasure room); Search DC 34; Disable Device DC 34

Now a competent 14th level rogue (max ranks +17, int +2, heroism +2, masterwork theives tools +2) might be able to disarm it on a roll of 11 but it seems inordinately deadly for its CR even so.

Anything I'm missing here?

I have toyed with very high CR traps in my previous epic campaign. There is no easy way to set the CR.

The simplest thing to do is to figure out who would survive it, what damage he would suffer, and set the CR according to his level.

Let's take your CR 16 trap: if the power word kill effect applies after all the previous effects apply, then I would most certainly raise the CR. The save DC's are somewhat easy to succeed, but only a rogue or monk will not be affected on a successful save. Most other PC's (barring energy resistance) will suffer more or less 50 HP, thus bringing them closer to the death range of the power word kill. The search DC is high, and it does happen that parties are rogue-less. Also, it affects mutliple targets.

All this combined, I would more or less set the CR at 18. I'm sure some will think that's too high. Some will think that's too low.

It's really not an exact science. Setting a high level trap CR is even worse than determining a new magic item's g.p. value.


edit: consider that trap yoinked !

 

[Gareman]

Powerful Traps

Try combining standard traps with appropriate monsters.

Here's one:

Disintegration Ray: (CR = EPL) The character steps into the trap and the gem eyes from a roomful of statues shoots rays at him. The PC is zapped and appears to be disintegrated. A skeleton appears in his place. It's important that the PC's don't get a chance to detect this trap or they'll quickly find a solution (Search DC45).

The character is teleported to a sealed tomb filled with the skeletons of various victims. A black pudding, CR equal to the party, attempts to engulf the teleported PC and turn him into a skeleton with its acid. When the trap goes off, one of these skeletons is instantly teleported to where the PC was standing, making it appear like he was disintegrated.

Make a Search DC 25 to notice the skeleton (pile of bones) is not the same makeup as the PC (DC 20 if the size category of the PC is one larger or smaller than medium). After six teleportations, the "living" victims (or their remains) are teleported back to the trap area. Defeat the trap by moving statues into the area so they can be teleported, eventually sending out "victims."

 

[jgsugden]

The traps system, in general, is flawed. Instead, I'd advise using the following house rules to assign experience for traps.

Whenever possible, fold traps into the CR of a neighboring monster that gains a benefit by the use of the trap. As an example, I had a CR 7 (normally) fire creature in a romm with a trap that set off an incediary cloud spell. The creature was aware of the trap and was immune to fire damage, so it liked to use the trap in combat to harm his enemies. This made the fire creature a much tougher enemy, so I bumped up his CR to 9 to account for the presence of the trap.

If there are no nearby creatures that can benefit from the trap, ask yourself what will be the effect if the trap goes off?

If it will be likely to significantly harm or kill/negate a PC, then a significant reward is appropriate for avoiding or surviving the trap. If the trap would be lethal to the PCs or would otherwise negate their usefulness (turn to stone, send to another plane, etc ...), a CR = to the average party level is fine. If it would only harm the PCs, a CR = to average party level - 2 is fine. Adjust these CRs to reflect the odds that a PC will find the trap if searching and to relfect the chances that the PCs would be effected by the trap in a significant fashion. For instance, a power word kill trap that will kill the PCs (no save) and is very hard for PCs to spot is worth a higher CR than the party level, while a delayed blast fireball spell trap that may kill the party (if it rolls high damage and if the party fails their saving throws) and is fairly easy to spot, although a deadly trap, is worth less than the experience for a CR = to average party level.

If the trap is not likely to significantly harm, kill or negate a PC, then it is probably not worth any experience. I call these hassles. They may delay a PC for a bit, but in the end, they really are nothing significant. When they create a danger, however, they should be treated like the traps that harm a PC, not like a hassle. An example of a hassle would be a hold person trap in the middle of an open field. So what if you get held for a few rounds if nothing is going to attack you during that time?