Bart Simpson's Treehouse of Horror #22

First of all, Bongo invites everyone to visit the Retirement Castle of the Vampires! Really... even your older, bloodsucking relatives need some attention. (Visiting hours are from 9 to 6.) Then, former couple Lisa and Nelson team-up to investigate paranormal activity at Springfield Elementary, prompting them to open The Ex-Files! And something's really strange in the neighborhood when the Ghost Bashers come to town!

Characters: Agnes Skinner, Bart Simpson, Bernice Hibbert, Bleeding Gums Murphy, Carl Carlson, Crazy Old Man, Doctor Marvin Monroe, Edna Krabappel, Grampa Simpson, Groundskeeper Willie, Hans Moleman, Helen Lovejoy, Homer Simpson, Jasper Beardley, Jessica Lovejoy, Kang (Simpsons), Kodos, Lenny Leonard, Lisa Simpson, Lunchlady Doris, Maggie Simpson, Marge Simpson, Maude Flanders, Michigan J. Frog, Milhouse Van Houten, Mister Burns, Nelson Muntz, Patty Bouvier, Principal Skinner, Professor Frink, Ralph Wiggum, Santa's Little Helper, Selma Bouvier, Waylon Smithers