In this follow-up to the hilarious hit, two parents, James (Travolta) and Mollie (Alley), decide to give their baby Mikey (voiced by Bruce Willis) a new baby sister named Julia (voiced by Roseanne Barr). Comedian Mel Brooks is also in for the ride as the voice of Mr Toilet Man, a fantasy bathroom bowl come to life, spitting blue water and eager to traumatize Mikey and interrupt his toilet training.