This is Mi Bone. He is a gorund/psychic type pokemon mix between Mr. Mime and Cubone. He kills everything and wears the bones and skin as a suit. And this is his story.
"A young bone wakes up in his nest to discover his mother missing. He waddles around to the outside in search of her. He stumbles through the night time woods and finds her down in ditch. He walks up to her, tries to wake her but she will not wake. He sees two shadowy figures come. A tall human with a large monster. He runs to hide behind some folliage and thinks to himself "This must be what a trainer is." The figure grabs his mother and walks away. He follows them to a cabin. As he peers inside he sees her being ripped apart by the trainer. Her skull thrown into the trash as her flesh is ripped into strips. He watches in sheer terror. "How could anyone be capable of doing such a thing? How could a pokemon watch one of its own be mutilated right in front of it?" He stays and watches the whole thing. From then on he was never right again."