Ma is a possum who first appears in the episode Smotherly Love, where her home was destroyed when the penguins were fighting Hans. The penguins easily fell for her possum act and she quickly settled into the Penguins HQ as their adoptive mother. But after Marlene told them about what possums do when they're in danger, the penguins threw her out, realising that they've been tricked. As they turn away back to the HQ, Hans captures her and confronts the penguins with his freeze ray. After freezing the penguins, Ma broke loose of the ropes and did her death act on Hans, who easily felled for it. When he came close feeling upset, Ma kicks him and grabs the freeze ray. She sets into reverse, freeing the penguins from their chill. Skipper says that she's welcome to come back and live with them but Ma decided to go take advantage of Hans back at the Hoboken Zoo.
As of Smotherly Love, Ma is still taking advantage Hans "trying to teach him how to be a good boy".
Ma has a very motherly attitude, since she raised 14 boys who moved out. She uses her "possum" act to make whoever she decides to "adopt" let her stay, as she did with the penguins, pretending to die every time they tried to argue. This is also how she is managing to stay with Hans at the Hoboken Zoo as of Smotherly Love.