The Cow King
From Diablo Wiki
The Cow King is the super unique boss of The Secret Cow Level in Diablo II. It looks just like any other Hell Bovine, there aren't any visual clues to identify it, except highlighting.
Bonuses:
Besides these two bonuses that always appear, the Cow King gains one additional bonus (random modifier) on Nightmare and two on Hell . One of the most annoying bonuses that it can get is Aura Enchanted. It can also hold a range of immunities and can be quite annoying for pure-elemental sorceresses and other element-dependant characters. This is the only boss to drop "The Cow King's Leathers".
Once he is killed, the Portal to the Secret Cow Level cannot be created again in the same difficulty. So, that makes the Cow King's Leathers the hardest set to complete in one game because there are 3 set pieces and the player gets only 3 chances to kill the King - one in each Difficulty.
Technically "he" can't be a king, but rather the queen, because a cow is female, the male is called a Bull.
[edit] Celebrity Status
The Cow King is known more for his infamy among the rumor mills than for his drops. Ever since his discovery as an easter egg, he has been associated with various other fake hidden eggs. He was supposed to:
- Be able to drop the Bovine Armor unique item from Diablo: Hellfire
- Be able to grant access to a hidden Hireling - the Angel in Act IV
- Be related to Lester the Farmer from Diablo: Hellfire
