Skog is a large green humanoid alien with fish-like characteristics, including scaled green skin, webbed feet and a fin on his head. He had a square face, three-fingered hands and black eyes with yellow sclera.
For a mission, Skog went to steal secret weapon files that would let his government destroy the "peace-loving nation" he was stealing from. As Skog was about to download the files though, Amy Rose intervened by ramming into his neck and pulling his collar while Tekno the Canary deleted his program. Hearing Amy's voice, Skog ran away in fear when Amy pretended to be Skog's conscience and told him he should abandon his plans. As he ran away, Skog decided to take up stamp collecting instead.