Cows have had a long history associated with pinball. Not that long compared to the whole range of pinball, going back to the Great Depression, but in the days of games with dot-matrix displays, it became a tradition to hide cows in pinball games in some way.
Just one example. In Attack From Mars, if you hit the Big-O-Beam ramp, sometimes the animal being enlarged is a cow. (If you can’t take your eyes off the game, listen for the woman saying “Would you look at the size of that cow?!”) Further, if you press the start button several times during this animation (each press will be punctuated by a MOO), it’ll turn the Saucer Attack minigame into Cow Attack, which is actually slightly easier I find; the hit detection is pixel-accurate, and the cows make for bigger targets. Here’s Cow Attack in action (one minute):
A history of pinball cows would take quite a while to explain, and that’s not the purpose of this post. No, what I’m here to tell you is that the legend of the Pinball Bovines has crossed to the makers of Metroid Prime Pinball on the Nintendo DS, which contains a cow! Here is video proof (33 seconds):
It’s explained in a saved interview on the Metroid Fandom wiki:
Remrod: “Indeed I am. I am renting two squash courts to store about 100 machines. But our DS version of pinball is more fun than the real thing!” (laughter)
Terasaki: “That’s right. There’s even an unexpected appearance from a cow.”
NOM: “A cow? What’s that got to do with Metroid?”
Barritt: “There was a pinball game in the 1980s called ‘Fire!’ in which a cow puts in an appearance. The game is about a huge fire that once broke out in Chicago. The cause of the fire was a cow kicking over a lantern. Ever since then, cows have become a fixture as hidden characters in pinball machines. This is well-known among pinball aficionados in Europe and the States, and perhaps around half of the pinball games released since then have featured a cow concealed in them. Naturally, we also put one in Super Mario Ball…” (laughter)
Terasaki: “If you do happen to find the cow, please leave it in peace!” (laughter)
The cow in the game has wings and flies around. Please, if you play it, respect this noble beast.