It's Halloween night and the kids encounter a strange boy named Russell who is convinced his 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 scary "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.
Elenco: Vincent Martella , Thomas Brodie-Sangster , Ashley Tisdale , Dan Povenmire , Dee Bradley Baker , Alyson Stoner , Bobby Gaylor , Maulik Pancholy , Caroline Rhea , Richard O'Brien , Kelly Hu , Mitchel Musso , Jeff 'Swampy' Marsh , Tyler Alexander Mann , Kari Wahlgren , Olivia Olson , Ariel Winter , John O'Hurley , Jane Carr , Malcolm McDowell , Barry Bostwick , Allison Janney , Madison Pettis .