Giant butt-eating Morty lived alongside his grandfather Giant butt-eating Rick in a dimension populated with giants. They created a small city which they could destroy. Rick Sanchez and Morty Smith from Replacement dimension visited them without knowing the scale to this dimension, and was attacked by their alternate selves.
Giant butt-eating Morty was not seen after the fight, leaving his fate unknown. His grandfather Rick was still looking for the intruders afterwards.