So last session i ran a trap for my players. Now my world is a homebrewed version of the real world based in victoria australia where magic and technology co-exsist. So the group got through a hallway similar to the laser grid from resident evil movie and in the next room were suits of magical metal armor and a door, the group put on the magical armor, which were equivilant to medium armor, thinking it was needed as protection for the next room.

The next room Was a large empty room with a locked door at the end. After some checks they deemed it all safe and begun to pick the lock, now in my game i allow ppl to take 20 on skill checks if they believe there isnt time restraints and they think its safe to do so, so the rogue took 20 on the lockpick check. After 10mins he heard a faint clink, he got through the 1st section of the lock, this caused the other door to close and a pit of acid to open up in the floor. With nothin rlse happening he continued picking, 5 mims later he heard another faint clink, he picked the second section of the lock, but this caused a humming noise to start in the roof above the acid. With nothing else happening he continued with the rest of the group preparing actions.

Now another 5 mins pass and with his passive investigation he realised he tripped a magical sensor in the lock. What came out of the roof was a metal ball that was magnitised, making anyone with the magical metal armor needing to do strength checks each round to resist being pulled and sruck on the metal ball.

What followed was a hillarious series of failed checks, ppl being flung upwards stuck on the metal ball, some shenanigans with an immovable rod and 3 ppl being stuck on this metal ball as it slowly lowered into the pit of acid.

The group survived with minor chemical burns. But when they asked why the armor was in the other room i explained that people who were meant to be here and not trying to break in knew how the trap room worked and knew the armor was there as a trap itself and without the armor the trap room was harmless coz it didnt work on any other type of metal.

I was kinda proud of how it turned out.