That's the Spirit! / The Curse of Candace

S3 E14: Michael Douglas and son Dylan star in this Halloween episode where Phineas and Ferb are enlisted to help a boy rid his house of ghosts. Meanwhile Doof becomes a were-cow. Candace sees a vampire movie and is terrified of becoming one. The boys develop gadgets to help friends do what they want, and use them to convince Candace she is a vampire.