Hey Ho (ヘイ・ホウ) is the first mini-boss of Sonic & Knuckles, and the seventh mini-boss of Sonic the Hedgehog 3 & Knuckles, fought at the end of Mushroom Hill Zone Act 1.
This mini-boss is the standard "easy first Zone boss". After making its appearance, the boss will fly to one of the trees and begin chopping away at it, sending chunks of wood flying towards the left. Upon reaching the base of the tree, the boss will get its axe jammed at the tree's base, and goes flying backwards once it pulls free, then flies off to cut down another tree. The boosters underneath the boss will also hurt the player unless they have a Fire Shield. Without the Fire Shield, the player must either hit the boss from underneath inbetween swings, or wait for it to get its axe jammed, attacking twice in this period if they're quick enough. After six hits, the fight will be over.
Knuckles has a slightly more challenging fight, as he cannot hit the boss when it is at its highest, and some of the log chunks will bounce on the ground. When the boss reaches the bottom of the tree, it will successfully cut away the last chunk and launch its head at Knuckles. Once the head reattaches itself to the body, the boss will then swoop down at Knuckles before flying off to the next tree.