"Don't Have a Cow" is the second episode and Halloween special in the second season of the Disney Channel television series That's So Raven, which aired on October 17, 2003.
The disappointed Victor allows Cory to go with his friend William, whose costume is a remote control that causes nearby electrical products to malfunction.
Eddie comes to the house to take them to the party, but they force him to leave as they start mooing sporadically and allow him to take the spell book to go with his sorcerer costume.
Raven suggests that they go to the party and get the book back to find a way to undo the spell, believing that the students won't question their appearances on Halloween.
At the party, Raven and Chelsea struggle to find Eddie as their bodies continue to change (such as developing snouts and hooves) and they begin to display cowlike behavior such as eating straw and chewing cud.
When they finally locate him, Chelsea eats the book page they needed to reverse the spell just as Alana's friends halt the party to announce the costume contest results.
As the students applaud them, Raven and Chelsea appear on all fours fully transformed into Holstein cows due to the spell's completion.