Costume Quest

Costume Quest is a party-based role-playing video game developed by Double Fine Productions and published by THQ on October 20, 2010. In the game, the player controls a child who is trick-or-treating with their twin on Halloween night when they encounter a monster that kidnaps their sibling. The player must travel around the local neighborhood collecting items for their costume, candy, and fellow children as companions in order to face the leader of the monsters and rescue their sibling. The costume aspects are used in turn-based battle segments, where the player character and companions are transformed into whatever they are dressed as to fight other monsters; the costume aspects are also used for abilities outside of battles.

A DLC expansion titled "Grubbins on Ice", was released on December 21, 2010, taking place after the events of the original game and set in the monster world of Repugia. A sequel, Costume Quest 2, was released in 2014.