Millstone
Millstones are large stone wheels that are often piloted by Gnawties.
Millstones first appear in the game Donkey Kong Country. They are often found in levels featuring temples, such as Millstone Mayhem and Temple Tempest. Millstones will either chase Donkey Kong and Diddy Kong through a level or act as obstacles blocking the Kongs' path.
Millstones make a cameo in the game Mario Superstar Baseball. A discarded Millstone can be found in Donkey Kong Jungle.
Millstones make their latest appearance in Super Mario Galaxy 2. They share some similarities from their past appearances, but they now take on the shape of a large stone gear and no longer have holes in the center. There are also non-damage-dealing ones that rotate in the same place, forcing the player to use their rotation to scale the walls and platforms inside. They are mainly found in Clockwork Ruins Galaxy.