The Cows of South Park are a herd of cattle owned by Farmer Carl Denkins. They had two major appearances, first in the Season One episode, "Cartman Gets an Anal Probe" and the other in the Season Two episode, "Cow Days". They are seen most often as background characters.
In "Cartman Gets an Anal Probe", alien Visitors are mutilating cows. The Cows try to escape the mutilation by train, but are rebuked by the train conductor for being cows and not people, "Hey, you cows can't get on this train! This is a people train!", The mutilations were caused one of the aliens named Carl by accident because he was new to the job. It is later revealed by the alien visitors that cows were the most intelligent on the planet.
In "Cow Days", a county fair is held honoring the cows as the title of the episode suggests. A giant cow shaped memorial clock is presented to the townsfolk leading off the annual "running of the cows" in which the cattle are supposed to stampede through South Park chasing the townsfolk. The cows steal the cow memorial clock and push it to an open field, where they begin to worship it as an idol. The FBI shows up to disperse the "cow cult", but is unsuccessful when they all commit suicide by jumping off the cliff.
The cows of South Park all resemble typical dairy cattle. They usually have a combination of black, brown, or white fur, and pink utters. The cows have traditional South Park-styled eyes and short horns.
Let's Go Tower Defense Play!
Although it's canonicity is disputed, cows are minor villains in the video game South Park Let's Go Tower Defense Play! on the opening level Stan's House. They are slow moving, easily defeated and drop more coins than other characters. They do not reappear in any other levels.