What do you do after you hook the sun, dredge up islands for humanity, and bring fire to the world? How about settle down with a nice goddess, have some kids, and enjoy the simple life. Nevermind that your new spouse's evil ex is on the way...and he's a vicious, monstrous eel. You have nothing to worry about! You're Maui! You have a...fishhook? Ok maybe you do have something to worry about.
The creature is the family tension that leads to you turning someone into a vicious, blood-thirsty firefly.