The Simpsons season 21 episode 4 | Watch The Simpsons season 21 episode 4

The Simpsons season 21 episode 4 by tittle “Treehouse of Horror XX” airs on Sunday October 18th, 2009 at 08:00 pm via FOX. In this episode This year’s triple threat of Halloween hilarity sees Moe using Homer’s blood for beer, Bart and Lisa caught in a murder pact, and everyone in Springfield becoming zombies thanks to Krusty Burger’s latest sandwich