A Chuck Guy is a spear-wielding Shy Guy that lives in the Beanbean Kingdom. They highly resemble the Spear Guys that live on Yoshi's Island and the Jungle Guys that live on Lavalava Island. They attack by either charging at Mario (or Luigi), stabbing Mario (or Luigi), or by calling in more Chuck Guys.
Purple ones live in Chucklehuck Woods, while blue ones live in Guffwha Ruins. Despite appearing late in the game, blue Chuck Guys are exactly the same as purple ones.