Every good trapsmith knows about the three C’s: Cheap, Crude and Cruel. The correct application of the three C’s while designing a trap gets you the desired result when the PCs have to decide whether they want to risk pushing on for “just one more room.”
And nothing is as cheap as a hole in the ground, so let us examine two common designs for pits, and how to improve them. [More…]
Camouflaged Pit Trap
CR 1; mechanical; location trigger; manual reset; DC 20 Reflex save avoids; 10 ft. deep (1d6, fall); Search DC 24; Disable Device DC 20. Market Price: 1,800 gp.
Deeper Pit Trap
CR 1; mechanical; location trigger; manual reset; hidden switch bypass (Search DC 25); DC 15 Reflex save avoids; 20 ft. deep (2d6, fall); multiple targets (first target in each of two adjacent 5-ft. squares); Search DC 20; Disable Device DC 23. Market Price: 1,300 gp.
For a hole in the ground, both traps are quite costly. Durability seems to be a factor in the design: their internal workings are sturdy, so they fail the crude check. Finally, neither trap passes the cruel check: the lethality of these traps from the DMG is quite low.
Improved Camouflaged Pit Trap
CR 1; mechanical; location trigger; no reset; DC 24 Reflex save avoids; 20 ft. deep (2d6, fall); pit spikes (Atk +10 melee, 1d4 spikes per target for 1d4+2 each); Search DC 24; Disable Device DC 10. Market Price: 1,500 gp.
After it is sprung, the improved camouflaged pit trap becomes an obstacle for future intruders. That is, the pit spikes at the bottom can still claim victims if a Jump or Climb check is failed, or if someone is pushed in during combat with a simple Bull Rush or gust of wind.
Even Deeper Pit Trap
CR 1; mechanical; location trigger; repair; hidden switch bypass (Search DC 25); DC 15 Reflex save avoids; 40 ft. deep (4d6, fall); multiple targets (first target in each of two adjacent 5-ft. squares); Search DC 21; Disable Device DC 15. Market Price: 200 gp.
Sacrificing quality to increase lethality. Sometimes, hard choices are easy to make.
Average damage output for these improved traps is one to two levels above the traps challenge rating—be careful.
Some quick design notes on the improved camouflaged pit trap show how the CR was retained at 1.
No reset: we are saving 500 gp.
DC 24 Reflex save avoids: we increase the DC to enhance lethality, but we keep it under the CR boosting level of 25.
20 feet fall: 2d6 damage averages to 7, which gives us a CR of 1.
Pit spikes: These increase the CR by 1.
Search DC 24: keeping it under 25 just like the original.
Disable Device DC 10: lowering the DC makes the trap cheaper and gives us a -1 modifier on the CR.
The result is a CR 1 trap, from base 1 + 1 + -1.
Design notes on the Even Deeper Pit Trap
Repair: by spending 40 gp you can reset this trap—quite a good deal—and we are saving 200 gp.
Hidden switch bypass: the bypass means we can place the trap in a high traffic area, so we need to keep it.
DC 15 Reflex save avoids: We need the -1 CR modifier. It weakens the lethality of the trap, but we must keep it.
The 40 foot fall gives us 4d6 damage and averages to 14 damage. This gives us a CR of 2.
Multiple targets: another +1 CR.
Search DC 21: now only characters with the trapfinding class feature can find this trap, and it only costs 200 gp.
Disable Device DC 15: we need another -1 CR modifier, and dropping Disable Device to DC 15 gives us that and it also decreases the cost.
Overall, then we are still at a CR 1, from a -1 + 2 + 1 + -1. Voila, a 40 foot pit that can appear in low-level scenarios!
Like our series on trap tweaking? Like us to ramp up the CR? Let us know in comments!