Master Claw is a monster which can be found in various trees in The Graveyard and in the Palace of The Guy.
If The Kid is close to the tree which a Master Claw is hiding in, it will attempt to kill The Kid with his hand by methodically reaching up and down. It cannot be killed.

The Tree Monster
Enemy
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Ryu - Hungry Spikes - Medusa Head - Snifit - Dumb Bugz - Zombie - Bullet Bill - Link - Metroid - Witchy - Waddle Doo - Master Claw - Cheep Cheep - Security drones - Hawk - Fly Guy - Gutsman - Fireball - Bob-omb - Sniper Man - Zoomer - Skree - Rinka - Fruit Monster - Magikoopa - Eggplant |