So how does WoW fit into all of this?
Well it all goes back to the original Diablo when fan rumors circulated about a special cow level — only no such area actually existed. Blizzard became aware of the how much attention this fabled level generated, and decided to create a portal that allowed players to battle against a legion of cows that had even included a massively challenging end boss known as Cow King.
Now bringing it back to the present day era, MabusGaming did some digging through World of Warcraft: Legion and discovered a variety of spells called “Moo,” “The Secret Cow level,” and “Summon Portal to Cow Level.”
This evidence suggests that Blizzard might bring back the bovine tradition and reward players for participating in the Diablo 20th Anniversary event. According to Polygon, once players unlock the achievement, it will be followed by a popular Diablo 3 message “There is no cow level.”
We can only speculate that Blizzard will surprise fans next week at Blizzcon, but until then, it’s best to take this information with a grain of salt.