Maj is a Maxis-made creature, present in the final game.

Maj is a green-scaled biped with yellow striped limbs and a light grey underbelly. It possesses a Grubblemaw mouth, Grumpeye eyes, Overhear ears, Batboy ears on its head and tail, Velocigraspers graspers, Scareclaw feet, and six Osteoflippy detail parts on its back.

Notably, there are two identical creatures called Maj in Maxis' Sporepedia. (both have the exact same abilities) This is probably a mistake by Maxis.