Cow goes Moo

Interesting info about the Cow level I saw on Wiki-

The phrase "There is no cow level" is a running joke started by the company's game designers stemming from repeated rumors on Battle.net that a "secret cow level" existed in Diablo. The phrase "There is no cow level" was a cheat code in the original StarCraft game. In Diablo II, a cow level was made as a secret level. "There is no cow level" now also appears as a 'tip of the day' on the loading screen of World of Warcraft.