To start the Chess Piece Easter Egg, we first need to find a small knight figurine. It can be found in one of three possible locations:

• Tavern Cellar
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• Courtyard in the room with Elemental Pop
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• Dining Hall Passage
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Once you’ve found the figurine, interact with it to pick it up. Then, head to the room where Stammin’ Up is located. It’s important to start this step at the beginning of a new round. If there aren’t enough zombies, the Easter egg will fail.

In the room, you’ll find a chessboard on the table.

Interact with the chessboard again to place the knight figurine. It will now hover above the board in a purple orb, and you’ll see a circle appear on the ground.

In this circle, you need to kill enough zombies. Once you’ve completed this successfully, a knight will appear and start hopping behind you, helping to kill zombies as well.