Cartoon Network Universe: FusionFall was a massively multiplayer online game developed by Cartoon Network and Grigon Entertainment. FusionFall uses the Unity engine as its client technology basis. For the first year, the full game required a subscription; free accounts could only access to a portion of the content. On August 29, 2013, the game's servers were shut down. Since the game's shut down fans have been working on ways to bring it back, going so far as to revive the game themselves, similar to Toontown Rewritten. There are currently two servers in development, one server based on the original game and another with additional fan-made content.