Steel cage

A steel cage is a trap that can be constructed in the Throne Room of a player-owned house. It requires level 68 Construction to build. When it is activated by a lever, it simply comes down on the floorspace, trapping people that happen to stand on the floor mat. Anyone can release the prisoner from the cage. Unlike the trapdoor, the person trapped can not escape.

Trivia

 * While the house owner is trapped in the cage, the butler will teleport a visitor into the cage with them. The visitors will remain trapped in the cage until they are released or leave.