This 15-foot-deep pit emanates tangible necromantic energy that slowly transforms creatures into undead. Within the pit churns a swarm of bodies—dead, dying, and undead, all writhing and clawing in various states of transformation. Rather than account for each creature in the pit, simplify the encounter by treating it as a trap.
Any living creature falling in the pit lands in the grasping arms of ravenous death. The creatures within grapple the individual, then try to tear him apart and devour him alive.
Changing Pit Trap CR 5
Type mechanical Perception —; Disable Device —
Trigger location; Reset —
Effect Atk melee +10 claws and bites (grapple plus 4d6). A hit means the creatures attempt to start a grapple (grapple bonus +10). The mob attacks every round. If a victim breaks free of the grapple and still has a move action, he can attempt a DC 18 Climb check to climb out of the pit.
The mob is easily damaged by weapons, spells, or other attacks. If a single attack deals more than 10 points of damage to the mob, it releases their victims. The pit-mob is AC 8 and 150 hp. Once it takes 75 hit points of damage or more, the mob disbands into 6 festrogs. Each round a living creature is in the pit he must succeed at a DC 15 Fortitude save or take 1 point of Con damage. Eventually, dead bodies in the pit (whether killed by the pit’s energy or otherwise) reanimate as festrogs.