Minecraft wiki entry for Traps, associated text: This trap will probably involve a trip to the Nether. After gathering a fair amount of magma blocks, make a room. Use the magma blocks you have gathered to make the floor of the room, and cover ALL the magma blocks with carpets. When the target walks on to the carpet, they will take damage from the hidden magma blocks, often wondering and unable to figure out where the damage is coming from. If they don't figure out the trap soon enough, they will eventually die or lose a lot of health from fire damage.