Here's my theory in full:
Gordon was from a planet where everybody looked like the giant monstrosity Max became.
He gave Max the psychic toys so that he could use them to restore Gordon.
He merged with Max upon his 'death' on board the ship because he was so weak.
Max used the toys and the psychic powers helped Gordon to regrow again - taking over Max like in the last episode.
It's About Time I Get Double Visions of Citizen Brown.