"A mask inspired by those fun-loving Koroks. It shakes when one is hiding nearby. If sold, this rare find can’t be replaced."
The Korok Mask is a special piece of armor found in Breath of the Wild. It has a base defense of 1, and was released as a part of the first DLC expansion for the game: 'The Master Trials'.
It helps Link to find many of the hidden Koroks scattered across the land of Hyrule. If Link is in close proximity to a Korok, the mask will begin to rattle and shake, whilst also emitting particle effects, similar in appearance to the Koroks' fairy lights.