Ever since Diablo 4's release one mystery has loomed larger than all others: Where is the cow level? Despite producer Rod Fergusson quickly pouring cold water on the idea, the history here means that a group of dedicated players has devoted themselves to finding a level that officially doesn't exist, and they've certainly found a few breadcrumbs along the way.
To briefly recap that history, there is no cow level in 1997's Diablo, but rumors of one became so pervasive that Blizzard North would later include a cow level in Diablo 2, one eventually appeared in Diablo 3, and the cows even had a nod in World of Warcraft. Heck, it's significant enough to have its own Wikipedia entry.
The latest development (as spotted by WoWhead) is the discovery of new relics related to Diablo 3 in the Vessel of Hatred expansion, eventually leading to an item called the Rusted Bardiche. Again it's the Now Finding a Cow Level crew that are doing their very best to not find a cow level, in this case finding three Scrolls of Uacax in the Kurast Docks, Samuk, and Kichuk. Each item's description contains hints about the history of Lord Uacax, with the final reveal being that the name Uacax itself may be a rough translation, meaning "Lord Cow" in Yucatec Maya.
From here, players have to jump through various hoops involving jabbering gemstones, and defeat the Elite Blood [[link]] Lightning in The Great Shelf with reference to one of the above scrolls. It says Uacax defeated the monster "untrained in combat", and so the trick is to reset all of your character's skills and abilities, dismiss any mercenaries, and then beat the thing with your basic level 1 attack.
After obtaining this relic, the next relates to the scroll linking birdsong with bells: players have to run across the Five Hills subzone, visiting 12 different bird statues, before the bell drops at the last statue.
We've already gotten quite into the weeds, but now you need to get into the mushrooms: players have to kill three Cordycepic Zombies north of Ichorfall, in such a manner that they spawn a patch of black mushrooms. Players then drop all three relics in here, corrupting them and giving off a purple smoke animation.
Then it's off to the Oka'bo Temple to offer up the three corrupted relics to three braziers, rewarding you with an Unusual Key, which can be used in the Forlorn Burrow in Kurast Bazaar. In a cellar there's a breakable wall, behind which are… cows.
Slaying all of the innocent cows will reward you with the Rusted Bardiche and… well, that's how far [[link]] we've managed to get. The discovery of actual cows marks this discovery out as one of the more significant made in the search for Moo Moo Farm, and what's perhaps more exciting is that this is all very carefully worked out: Yes the hoop-jumping is a bit much, but everything players are doing here is trailed in the in-game text, and there's a definite thread of logic from start to finish.
The Not Finding a Cow Level Discord continues its tireless work. And Blizzard's ready for them, with associate game director Joe Piepiora saying last year that "if people have picked up any items from their cow campaigns, they should hang on to them". So keep a hold of that Rusted Bardiche.