From the Super Mario Wiki, the Mario encyclopedia
In The Adventures of Super Mario Bros. 3 episode "Dadzilla", Kootie Pie and Big Mouth, upon arriving in Hollywood, think that Madzilla is their real father, due to the way that Bowser treated Kootie Pie earlier on. The two Koopalings use their magic wands to bring a mechanical Madzilla to life.
Mario then devises a plan to build their own robot out of spare parts in the warehouse to play the role of Madzilla's Mom. In the interim, Madzilla is told to steal the Hollywood Bowl so that Big Mouth and Kootie Pie can perform their own concert. After the concert receives a poor reception from the public, Madzilla picks up several innocent people, whom he threatens to toss in the Pacific Ocean. Before he can do so, Madzilla meets up with Mario's robot, which he believes is his mother. While controlling Madzilla's Mom, Mario tricks "Junior"'s "children" into fleeing by insisting that everyone in their family must take naps so that they are rested to do their chores. Not wanting to stick around, Big Mouth and Kootie Pie run back home.
She seems to be made out of a monster head, a dragon body and right leg, a gorilla's right arm, a sea monster's left arm, and a giant's left leg. She also has the power to exhale steam from her nostrils.