Costume Quest is a result of a series of "Amnesia Fortnights" that Double Fine had used during the period of Brütal Legends development when they were unsure of their publisher. During the Amnesia Fortnights, the team split into four smaller groups and worked on prototypes for potential future games, later presenting these to the rest of the Double Fine team for review. All four prototypes were well received internally, and the ideas were set aside once they began work on Brütal Legend again. Following completion of that game, Double Fine believed that Electronic Arts had authorized them to continue work on a Brütal Legend sequel, but discovered later that the sequel had been put on hold indefinitely, leaving the studio with no projects. Instead, Tim Schafer turned back to the Amnesia Fortnight products and sought to develop those as smaller games among several publishers. Two of them, Costume Quest and Stacking, were picked by THQ for publication as downloadable titles.
