Dave the Barbarian (2004)

S1E31 The Cow Says Moon

Evil Princess Irmaplotz conjures a bizarre, milk-like creature to attack Dave after he swims in its milky depths, transforming him into a Were-Cow with the next full moon. As Dave wreaks havoc on the villagers, he encounters various bites, including one from a cat, an egg beater, and even his gym instructor. Eventually, the gang devises a plan where Dave bites his own tongue with a sheet of paper, turning him into Wear-Dave. However, Fang mistakenly believes he's still a non-weary Dave, and Dave returns to his normal self just as Irmaplotz is shocked by the gang’s unexpected success. The next morning, in a twist of fate, Dave accidentally bites Faffy, turning him into Faffy-Dave, who then joyfully sings "Funny Bunny."