Phineas and Ferb: A Phineas and Ferb Family Christmas

Candace is bitten by a bat after watching a popular vampire movie and worries that she is becoming a vampire. Phineas and Ferb's latest gadgets lead Candace to believe that she has indeed made the change from teenager to teen vampire. Meanwhile, Dr. Doofenshmirtz plans to change the Tri-State Area into a carbon copy of Gimmelshtump so it will be easier to take over./ It's Halloween night and the kids encounter a strange boy and his father who are convinced their house is haunted. Meanwhile, Dr. Doofenshmirtz's disdain for grass causes him to invent a "mind-transfer-inator" enabling him to merge minds with a cow and destroy all the grass in the Tri-State Area. Unfortunately, his plan backfires and he transforms into a "were-cow" that wreaks havoc any time there is a full moon. It's now up to Agent P to stop him and save Danville.