|Trigger: Mechanical: Proximity||Effects: Multiple Targets|
|Resets: Automatic||Bypass: None (Avoid)|
Description: The pit trap is bad enough, no? But wait, there's more! This can apply to any pit - in fact, you can roll a d6 for any pit and have any result of 1, indicate that the pit is infested.
If you think about it, the pit is a perfect environment for many monsters. Hidden and out of the way, avoided by the resident denizens, and your food comes to you! There are a variety of monsters that can survive in a pit for long periods of time, where the confined quarters and long waits are not bothersome. There are often small tunnels and such giving access to such pits.
Some monsters that might inhabit pits include: Giant microscopic creatures, beetles, fungus, insects, jellies, animated objects, mimics, mold, oozes, rats, parasites, shadows, slimes, stirges, and undead. A longer list is here.
It is suggested that the player roll a d20 with no modifier, to see if the creature in the pit is struck. If so, then the creature will take the same damage as the player falling into the pit. Note that striking many pit creatures with your body will have many negative effects of their own.
Detection: Detection is as any standard pit. Most of these monsters should be easily detectable once the pit is located and that is fine. Allow them to avoid your monster, if the monster is discovered. Of course if you were to place a magic sword, stairways, secret doors or even a lair could convince them to have the encounter anyway. If you are truly wicked, have the magic sword be worthless, the stairway a dead end, or the lair filled with nothing but monsters.