Boo Buddies are enemies from The Legend of Zelda: Link's Awakening. They are based on the Boo enemies in the Mario series. Like many enemies from the Mario series, they were placed in Link's Awakening as cameo enemies. They are ghosts, and only two appear throughout the entire game, both guarding the Power Bracelet in the Bottle Grotto. Similar to the enemies they are based on, they thrive in darkness where they are near invulnerable to attack. When exposed to light, Boo Buddies are severely weakened and will attempt to flee by phasing through nearby walls and escaping the room. At this point, they can be defeated by most weapons in Link's arsenal. In the dark, they are invulnerable to everything but arrows and the Magic Rod.
The name Boo originates from the word used in English used to surprise someone as part of a practical joke, usually by ambushing them unexpectedly and shouting the word at the same time.