With a few personal tweaks, you can use this trope-twisting trap in pretty much any setting or time period that has traps (a dungeon, a secret lab, etc.)(fantasy, modern, future, etc). I used it in a fantasy setting.
My players were delving into tunnels that led to the secret labs of a crazed wizard. After some failed attempts at gathering information, they only found one entrance. Two gargoyle statues embedded into the stone flanked the mouth of the cave.
Inside the tunnels were dark, limiting their vision to what their torches illuminated. The tunnels were setup as roughly 30×30 room with a 15×5 hallway connecting them. The cave looked natural, so the dimensions varied slightly in each room. Stone gargoyle busts (that’s a sculpture from the chest up not just gargoyle boobies) clung unevenly along the walls of the cave in no discernible pattern. Each room had 3-5 of them. However, none of the gargoyle busts sat near the hallways.
After walking for a while, as the players were about to leave one of the larger rooms and enter one of the hallways, the stones above the halls on either side of them shifted. They each rolled a reflex save as a large stone door fell to block the hallway.
I wanted players on both sides of the door, so I made sure the reflex save was not too high. To my delight, I successfully split the party, putting one half one each side of the stone door. All the players holding torches made their saves, leaving the trapped players completely in the dark. They tried to communicate, but the thick stone muted their voices some, making verbal interaction difficult.
The players trapped in the room heard liquid pouring and hitting the floor all around them, but they felt nothing. As expected, they surmised that since they were in a sealed room, the room would fill with water and drown them. Both sides struggled to lift the door. I made the DC for the strength check rather difficult. I wanted the players to fail at least a few attempts.
As they tried to lift the door, the trapped players heard several quick, sharp metallic noises coming from inside their room. With a high enough listen check, I let them recognize it as flint and steel.
After a few clicks, an open flame ignited inside all of the gargoyle’s eyes. The light reveals the gargoyle’s mouths were spewing a thick, black liquid that was slowing spreading across the floor. After a lofty intelligence check, I informed a player they recognized the sight and smell of it. It was a highly flammable oil.
The gargoyle’s stop spewing oil just as the flames fall out of the gargoyle’s eyes and hit the oil, igniting the floor. The flaming oil continued to creep across the floor, closing in on the trapped players. I wanted my players to sweat (pun intended) and panic more than I wanted them to die, so I made sure they had 1-3 rounds before the flaming oil sludged over to them and set them ablaze.
After a hilarious struggle, my players did get out, though a critical failure on the strength check to hold the door up made it slip from one player’s hands and crush the legs of one of the escaping players. The fire burned no one but traumatized everyone. It was great.
For bonus points, have rock monsters, cave-dwelling creatures, skeleton warriors, or some other appropriate enemy come from the opposite way and attack the players that made their reflex saves, forcing them to divide their interests between getting shanked while helping their trapped party members or protecting themselves and leaving their party members to burn.
With this trap, you can watch your players suffer and bathe in their sweet, sweet misery.
I’m going to experiment with the best format for these posts (write it in short, quippy bursts, write it like a recipe, and so on). If you have a suggestion or a comment about the writing style or the trap, leave it in the comments.
Never forget to laugh maniacally.