Both sides were interested in developing a Treehouse of Horrors overlay while the ride was originally in development. However, the TV writers strike in 2007-2008, plus the extended contract negotiation with one of the voice actors, forced the ride to be developed on a compressed timeline. To account for that, they eliminated the Treehouse aspect from the conversation, with plans/hopes to revisit it later. However, it never did, for various reasons. Mostly because the costs/time requirements of NEW negotiations strictly for an overlay aren’t worth it.