Hook Guy is an enemy in Yoshi's Woolly World. It's a Shy Guy that carries a yellow crochet hook they behave similar to the Spear Guy. Most of them can found walking from side to side while the hook's in front of them.
Some can be found suspended in the air by balloons while holding the hook downwards. The balloons will pop if they're hit by a Yarn Ball or if Yoshi or your Yoshi goes underneath them.
In addition, their hooks can pop bubbles as they fall down. If a Yarn Ball hits the front of the hook, it'll attach to it. They can be defeated by Swallowing them from behind, then spitting it out.