Animator Lee Hardcastle spoke to IndieWire about turning a one-off gag in an episode of the surreal animated series into a full-fledged horror short. Nobody takes the famously unserious holiday of April Fools as seriously as Adult Swim . For 20-plus years, the programming block has used the holiday as an excuse to pull off all types of immersive stunts, from rebranding to “Adult Swim Jr.” to surprise premiering their shows. And for 2026, the channel pulled off its creepiest prank yet, with a