Raven and Chelsea were upset that they weren't invited to Alana's Halloween party hosted at the Chill Grill. While having dinner there, Chelsea eats Raven's hamburger instead of her veggie burger due to Victor accidentally swapping their plates. This greatly upset her as she was a vegetarian.
They later go to Raven's house, where Chelsea started wearing an anti-beef pin with a cow's face on it out of guilt. The two begin digging through a chest filled with paranormal artifacts belonging to Raven's grandmother, Viv, and find a book titled, "A Book of Potions, Spells, and Incantations," which offered various magical spells. After Chelsea finds a spell that can grant any wish, Raven gets an idea.
The two prepared a concoction inside a cauldron and tried casting the spell to be invited to Alana's party. They immediately received a call confirming their invitation from a hypnotized Alana. Now knowing the spell works, they then wished to be the most popular girls at the party and to have the best costumes. After casting the spell, they failed to notice Chelsea's cow pin fall into the cauldron from their excitement before heading upstairs.
While trying to figure out costumes to wear, Chelsea noticed that Raven's ears were shaped like a cow's. They start panicking after realizing Raven's actual ears have changed and are further frightened to find a long, white tail on Chelsea's rear. After they both developed cow ears and tails, Eddie arrived at the house to take them to the party.
Raven and Chelsea hid their cow parts from Eddie and forced him to leave. Before he left, Eddie asked if he could borrow the spell book to go with his wizard costume. They let him keep it as Raven started mooing sporadically.
The two realized that they were slowly turning into cows after finding the pin in the cauldron and were unable to reverse the magic since they lent the spell book to Eddie. Raven determined that their only option to stop the spell was to go to Alana's party and get the book back, figuring that they could show up to the party looking like cows on Halloween.
Raven and Chelsea eventually arrived at the Chill Grill and tried to find Eddie as their bodies and mannerisms were becoming less human and more bovine. After locating Eddie and the spell book, Chelsea ended up eating the page with the reversal spell. With their one chance at stopping the spell gone, Raven and Chelsea completely transformed into cows. Despite becoming farm animals, they still got their wish to win the costume contest, so they decided to "milk it."
It is then revealed that the whole night was a vision Raven had right before Chelsea ate the burger. She immediately stops Chelsea to prevent the ordeal from happening. It is unknown what would have happened to Raven and Chelsea if the vision came true and if they would have remained cows permanently.
For the majority of the vision, Raven and Chelsea retained their human physiques but slowly became more cow-like as it went on. While they originally hid their cattle parts from Eddie at the house, they did not hide their features at the party as people would interpret their changing bodies as Halloween costumes. Before the costume contest announcement, during which the rest of the transformation occurs, they had cow ears, tails, snouts, hooves, and tongues.
They also demonstrate inhuman abilities such as chewing cud and mooing in significantly lower-pitched voices, potentially hinting that their digestive systems and vocal cords were changing as well.
At the end of the vision, Raven and Chelsea end up becoming white and black furred Holstein cows, but they still retain their human hair in their new forms. When they fully transformed, their clothes disappeared and they somehow gained halters on their snouts.
The spell also caused Raven and Chelsea to act more like cows. While they were initially horrified and disgusted at the animals they were becoming, they increasingly gave into their bovine instincts as the night went on.
The most notable sign was their mooing habits. At first, they lacked control over their urges and would instinctively low whenever they said a word that rhymed with "moo" before quickly covering their mouths, but they eventually began doing it frequently without having to say a trigger word and made no efforts to stop themselves.
At the party, they developed ungulate appetites and eating habits. Chelsea displayed this more by chewing on someone's straw hat, eating the spell book page, and drinking out of the punch bowl with her face. While Raven condemned Chelsea for these actions, she also was not immune from similar cravings as she started chewing cud and did not realize it until Chelsea pointed it out.
When Raven and Chelsea are fully transformed, they supposedly retain their human minds and can still talk, though the extent of which is unknown given the vision's ambiguous ending. The final shot on Raven's eye may also imply she still has her psychic abilities.
"I have cow ears? How did I get cow ears?"
"We wished we were cows? Why couldn't you have been wearing a Halle Berry button?"
"You are not a cow! You are a human being!"
"It's not gum, it's cud."
"Mind as well milk it!"
"All right, take it it's yours, now just moooooooooove."
"Me? Moo? Noooooooooo!"
"It's truuuuuuuuuue. We really are cows!"
"Cow, Cow, where art though? You're in my stomach now."
"Hello; I have a zit AND a tail!"
"Hello, Rae? We cannot walk into a room full of people looking like cows!"
"Hold on, Rae; I only have two hooves!"
"Yep, all eyes are on us..."
"Eddie has taken the book; we are definitely doooooooooomed."
"Mhm, mm, and it's gooooooooood."
- Raven and Chelsea are not the only Disney Channel characters to be turned into cows, as Dave on Dave the Barbarian and Dr. Heinz Doofenshmirtz from Phineas and Ferb were also turned into cows (though the term cow is correct with Raven and Chelsea as cows are female cattle). They are the only live-action Disney Channel characters to turn into cows.
- There are a couple of physical differences between the two as cows:
- Their human hair colors (Raven's is brown, Chelsea's is red)
- Their halters (Raven's is brown leather, Chelsea's is gray rope)
- Their snout colors (Raven's is black, Chelsea's is pink)
- Their sizes (Raven is significantly taller and larger)