Once upon a time, a popular, yet entirely untrue rumour popped up concerning Blizzard Entertainment's seminal hack-n-slash RPG, Diablo. Specifically, that there was a super-secret level you could only reach by doing something to the harmless cows chillaxing in the town of Tristram. Some said you had to open a scroll of town portal, some said that you had to poke them (to initiate dialogue) hundreds of times, there were multiple variations on the theme. The "Secret Cow Level" as it was referred to, was said to have the most powerful weapons in the game and super-powerful adversaries to use them on. Eventually the name got mixed up in the myth itself, and people said that the Cow Level contained cattle-themed versions of all the game's enemies, such as acid spitters which sprayed milk on the player, or Goatmen who were actually Bullmen, all led by the Cow King, an ultra-powerful boss said to be stronger than Diablo himself. As previously stated, all such rumours were filthy lies, and there was no Secret Cow Level in Diablo.
In Diablo II the cow level is at last a reality; accessible only by combining Wirt's Leg, the peg leg of Wirt (a resident of Tristram in Diablo) and a Tome of Town Portal in the Horadric Cube. This will open a red portal in the Act I Rogue Encampment, which will teleport the player to the Secret Cow Level. This level is accessible in both the standard game and the expansion, Diablo II: Lord of Destruction, but only once Diablo has been defeated. The level is relatively small, a repeating wilderness area full of "Hell Bovines", cows that stand on their hind legs and wield large polearms.
The Cow King made manifest
In every instance of the cow level there is one unique Hell Bovine named "The Cow King" who drops some rare loot. Upon killing the Cow King the player will be unable to create anymore portals to the Secret Cow Level on that difficulty.
In Diablo III the cow level is a magical, colorful world of whimsy occupied by animated teddy bears, unicorns and flower creatures. Treasures are hidden inside birthday presents, pots o' gold, smiley clouds and pinatas.
- In StarCraft one of the cheat codes was "There is no cow level" which would instantly win the current mission.
- Since the introduction of the 1.20 patch for Starcraft 2 clicking on the Battle.net logo at the top of the screen 11 times sends a player to the "Cow Level Chatroom".
- In World of Warcraft there is both the "Cow King's Hide" and "Wirt's Third Leg", a leather chest piece and mace.
- Blizzard still officially denies the existence of a Secret Cow Level, even in Diablo II.
Light Crusader on the SEGA Genesis could be considered the "proto secret-cow" game. This action-RPG contained numerous cows, and while there was not any single specific secret cow level, there were secret areas containing cows. It's not known whether Light Crusader was an influence on the later Blizzard action-RPG Diablo II, although it's exceptionally unlikely.