The name Jack-o-lantern comes from a phenomenon of a strange light flickering over peat bogs, AKA Will-o-the-wisp. The Jack-o-lantern key goes to a clockwork jack-o-lantern that releases a swarm of wisps and a flood of eerie mist. The wisps possess Halloween decorations and change them into real monsters. The same thing goes for unfortunate people in costumes, they become the beings they're dressed as. The effects, wisps, and mist return to the clockwork jack-o-lantern when the key is removed.

Inspired by Locke and Key.