The Bremen Mask is one of the many masks you can find in The Legend of Zelda: Majora’s Mask. It’s an interesting item, though far from the most useful or memorable.

The character you get it from apparently stole it, but the mask itself has a deep connection to animals.

As the design suggests, the mask plays a notable role with chickens. When you use it to play music, it puts nearby animals—especially chicks—into a kind of hypnotic trance.

You use the mask to lead baby chickens and help them grow into full-grown hens. This process is necessary to obtain the Bunny Hood, which is one of the most important and useful masks in the game. One thing I didn’t know until later is that the Bremen Mask can also put the undead Ikana warriors into a similar trance. That effect is more useful than I originally thought, and I never realized it until much later in the game.