Kalraka Dzeik is a sentient lightning storm with a following of cultists. It has much in common with a natural disaster or a plague; it starts at a single point but spreads like wildfire if given the chance. It is capable of terrible destruction, and will take heroic effort to stop, if it can be stopped at all.
Have a large room that elevates either up or down when triggering a trap. The floor can bring the players to new levels, where a mighty beast roams, or the floor flattens the players into the ceiling or drop into a pit of lava.