Mask-Mimics are enemies from The Legend of Zelda: Link's Awakening. They are originally creatures from Nintendo's Mario series known as Shy Guys that make a cameo appearance in the game along with other enemies from the Mario series.
Their appearance is that of short humanoid creatures with strange masks protecting their faces. They move in synchronization with Link. An effective way to defeat them is for Link to walk towards them, jump over them with the Roc's Feather, and release a Spin Attack, damaging their vulnerable backsides. They can also be shot with the Bow.
As part of the Link's Awakening DLC, Zant has a Mask-Mimic Recolor of his Standard Outfit.