In Elmo Saves Christmas, Elmo wishes that it would be Christmas every day, but eventually learns that might not be such a good idea when he sees the future.
Because of Elmo's wish, the Elves at Santa's workshop have to work harder with Christmas suddenly coming every day, and mistakenly produce cows with bunny ears. Since they are exhausted, Santa agrees to deliver these new toys, calling them Moo-Bunnies.
At the end of the special, after Elmo goes back in time to the starting Christmas, Santa expands Elmo's choice of presents to include a Moo-Bunny, in addition to a pink bear and a magical snowglobe. Elmo chooses the Moo-Bunny.
The elves also create stuffed bunnies with cow horns and ears, called "cabbits".