From Technote
#31

What is a Dogcow?

I wish I had a nickel for every time I’ve heard this question—by now I’d
have enough money to buy a Changing the world, one person at a time
bumper sticker. Dogcows, by their nature, are not all dog, nor are they
all cow, but they are a special genetic hybrid. They are rarely seen in
the wild. Since dogcows are two dimensional, they will stand facing a
viewer “on edge” to avoid being seen.

The dogcow has no natural enemies, but the meager population manages to
keep itself in check through its own stupidity. They have a nasty
tendency to graze off cliffs (in fact, there are no known
“cliff-dwelling dogcows” left in existence) and to get lost in the
weeds. You’ve probably noticed that when you cut very high grass, you
tend to get a lot of “paper” in the grass clippings; closer examination
would show that much of it is actually dogcow. When a mower approaches,
dogcows often actually change their hide to resemble newspaper as a
final line of defense—hence the famous expression, “black and white and
read all over.”

Upon closer examination, I discovered that dogcows actually “speak.” In
a very excited condition, like being near an open can of Mountain Dew,
dogcows will say “Boo Woo” But it is much more common to hear
them just say,
“”Moof!“”:https://web.archive.org/web/20040202021201/http://developer.apple.com/products/techsupport/dogcow/moof.au

For a specific character example, see Clarus the
Dogcow.