Cornimer is a tortoise  that appears in the Animal Crossing series . He only comes out during the Acorn Festival in Animal Crossing: Wild World , and gives the player mushroom furniture, walls, and floors in exchange for acorns, which are obtained by looking under oak trees during the festival. However, if theplayer gives him a rotten acorn, he will say that all the other acorns the playergave him that time don't count. Much like Tortimer telling the player's fortune by using fireworks he can tell the player's fortune by using acorns, as shown below. It is believed by many that Cornimer is Tortimer wearing a mask.

Cornimer's head appears on the machine that the player must chase and whack with a hammer in the Hammer Island Tours in Animal Crossing: New Leaf. It is possible that the head is the Cornimer mask allegedly worn by Tortimer in Wild World, attached to a remote control car.