Maimaigoon(JP) is a psychopathic monster that is encountered in the Kirby: Right Back at Ya! episode "Shell-Shocked". He was created accidentally when Escargoon lost his shell and put on a steel-hard one purchased from Nightmare Enterprises, which turned him into a monster. He is fought by Hammer Kirby.
Maimaigoon bears very little resemblance to his old self. His concealed form depicts him with glowing green eyes, but when he makes his first appearance, the Maimaigoon does not appear to have eyes at all. His arms are stubbier, and his shell has two horns that allow him to fire a powerful laser known as a Mai Mai Beam. He is very, very large, about twice or thrice the size of King Dedede's limousine.
King Dedede's assistant, Escargoon, loses his shell after King Dedede himself uses his hammer to break it open to see what is underneath. Kirby goes out of his way to find the poor snail a turban shell, much to Escargoon's delight. Escargoon is later given a trick shell, but this turns out to be a mistake, as it engulfs him and mutates his body, and Maimaigoon is born. Just seconds after he is born, the monster tries to attack the gang. However, Kirby uses his Inhale to absorb King Dedede's hammer, resulting in his transformation into Hammer Kirby. Kirby destroys the shell with a hammer throw, and Escargoon reverts to his normal form and retrieves his old shell, which Tiff had fixed for him.