Aside from the single door through which the players entered, this circular room is completely featureless. Its only occupant is a swarm of plum-sized, multicolored insects buzzing about in a massive swarm. These insects produce a lot of noise, but don’t do much of anything else. It’s rather strange, actually. The swarm doesn’t react to the entrance of players, nor to the open door. Even if a player were to leap into the midst of them and waves her arms around, the bugs would just flit around her as though she were not there.
There are blue, yellow, green, red, violet, orange, teal, and lime colored insects in the swarm. These colors have no meaning. They are an obfuscation. Also, dungeons are not colorful enough.
The colors of the insects will be noticed at first glance, but it requires a moment of examination to notice that many of the insects bear aberrant features. Some have unusually large eyes, others have massive teeth, a few have tails, lots of them have stingers–though they will not sting, even if pestered by aforementioned arm-waving adventurer.
Attacking the tiny, fast moving creatures with a conventional weapon is a nigh impossible task. They have an effective armor of 24*. Catching them is actually much easier. Attempting to grab one with your hand requires an attack roll against armor 18*. If either of these attempts misses by 5 or less, it is a simple miss. If they fail by 6 or more, then the player hit/caught one, it just wasn’t the one they intended. Roll on the chart below to determine which. If the players use a jar or bag and sweep it through the swarm, they will catch 1d2 of the creatures without fail, but what they catch will be random. If they use a proper net, they’ll capture 3d6 creatures, but again it shall be random.
The aberrant features of each creature correlate to an effect. The moment they are damaged or captured, they will pop into a cloud of dust, and that dust will reform into whatever the bug’s type calls for.
1-2. Normal: No effect.
3. Bulging Eyes: A door appears on the wall. If there is nowhere for the door to go, then either a corridor is created leading to another part of the dungeon, or the door becomes a permanent, two-way portal to a random dungeon location. (50/50 chance that it is a location already explored, or a new location the players haven’t found yet). The GM may choose whichever option fucks up their map the least. Note that this is not a secret door. It does not exist before the bulging eyed bug is caught, and thus cannot be discovered before then.
4-6. Large Mouth & Teeth: The dust reforms into a monster from the random encounter table for this area.
7-9. Stinger: A trap appears, and is immediately sprung on the players. It could be a pit trap, or an arrow trap, or a collapsing ceiling, or whatever the GM fancies.
10. Tail: A chest appears, with treasure inside of it!
Note that this is only a very basic sampling of what might be present in the room. If the GM so chooses, there could be drooling bugs which create fountains with a random magical effect; bat-winged bugs which reverse the room’s gravity; bird-winged bugs which cause all of the adventurer’s gear to become animated and attack them; bugs with legs which grant the players a blessing; or bugs with a contented smile on their faces which grant enlightenment. As with everything in the game, the possibilities are quite endless.
*This is based off LotFP rules, of course. Pathfinder players would want to bump those numbers up significantly, while players of games with descending AC would want to drop them quite a bit. The idea is that this is a puzzle which a fighter is best suited to solve. There are many rooms which are best suited to a magic user, or cleric, or specialist/thief. I thought it would be nice if there was a puzzle which required a character to have really good to-hit rolls.