Walleye

Walleyes are Whomp-like enemies that first appear in the game Super Mario 3D World. They are similar to the Wallops in Super Mario 3D Land, with spikes on their sides and top.

Super Mario 3D World
Walleyes first appear in Super Mario 3D World as rare enemies. They move from side to side in an attempt to stop the player from walking past them. Contact with their spikes will cause damage, but their fronts and backs are safe to touch. Walleyes can be temporarily dazed by a projectile or a claw attack and can be destroyed by Lucky Cat Mario. They only appear in Ty-Foo Flurries, The Great Goal Pole and Mystery House Marathon.

Captain Toad: Treasure Tracker
Walleyes return as somewhat uncommon enemies in Captain Toad: Treasure Tracker, serving the same purpose as in Super Mario 3D World.

Super Mario Party
Walleyes will appear in Super Mario Party as non-playable characters.

Names in other languages
Guckiwummps Wallokkio