Momma Robotnik is the mother of Doctor Ivo Robotnik who is even meaner, crueler and more ruthless than he is.
She is kept in an asylum called the Mobius Home for Really Bizarre Mothers, though she escapes from time to time. Her insanity is enough to scare even Robotnik himself.
Originally a one-shot gag character for the episode "Momma Robotnik's Birthday", she found her way into the regular recurring cast about halfway through the series coming back for "Momma Robotnik Returns", "Zoobotnik", "The Last Resort", and "Sonic is Running".
Momma Robotnik has a very large figure, much like her son. She has black eyes with red/black pupils and blue/red irises and a pink nose like her son and wears a bulging pink dress, a large green hat and black shoes.
On the first episode she appeared on, she had a mustache just like her son's. In her next appearance the mustache was gone, however towards the end of the episode, Sonic ripped Robotnik's mustache off and slapped it on Momma Robotnik. From there on, her mustache would come and go. For example, she had no mustache in Episode 35, "The Last Resort", but then in episode 40, "Zoobotnik", she had a mustache again.
Momma Robotnik has proven to be a competent and dangerous enemy for Sonic, Tails and even her own son. Her physical strength is significant–on one occasion she was able to simply stampede through Robotnik's wall of defenses surrounding his fortress. In another incident, she engaged the alien huntress Katella in direct combat, and proved to be the only being aggressive enough to frighten the entity from the planet.
Momma Robotnik has demonstrated significant cunning and manipulative skill. Despite Scratch and Grounder's programmed loyalty to Robotnik, Momma Robotnik was able to quickly turn them against her son with only seconds of emotional manipulation. She was able to manipulate the Mobius local government's welfare department to grant her custody of Tails, allowing him to be used as a lure for Sonic. During Momma Robotnik's Birthday, she poised a trap that came extremely close to killing Sonic, and was only foiled through the direct sabotage of her son.
Momma Robotnik's rampages are usually stopped when the senior staff of the Mobius Home for Really Bizarre Mothers discover her escape. A high speed ambulance with orderlies is usually dispatched to apprehend her before her machinations cause any lasting harm.
Momma Robotnik has a cameo in the Off-Panel for Archie Sonic the Hedgehog Issue 275, where Mega Man ends up using the Mama Beam Special Weapon in a failed attempt at creating a spectacle for the fizzled 275th Issue celebration between himself, Sonic the Hedgehog and the Sonic Boom counterpart for the latter.