From the Super Mario Wiki
Squirpina XIV is the queen of Squirpia, a kingdom that once flourished in the depths of Outer Space. Although she is mentioned in Super Paper Mario alongside a statue built in her honor, she does not appear in-game. Squirps, her son, is the only character to talk about her.
1,500 years before the events of the game, Squirpina was visited by the Tribe of Ancients, who entrusted her with the Blue Pure Heart along with the knowledge of the calamity that would befall all worlds with the creation of the Chaos Heart in the future. Squirpina hid the Pure Heart deep within the Whoa Zone, an endless maze with a hidden entrance, and sealed her son, Squirps, inside a hibernation capsule, so that he could serve as the heroes' guide to the treasure when the time came. Squirps tells Mario and co. of his true nature as a prince and of his mother's fate as he stands beside her statue in the Whoa Zone. He brings Squirpina's mission to an end by passing onto the heroes the fourth Pure Heart. Afterwards, he falls asleep near his mother's statue, telling her he had done his best and wanting to know if she was proud of him.
Following the defeat of the final boss and the destruction of the Chaos Heart, Squirps can be found in the Whoa Zone, recounting how sad he was when his mother left him and promising to restore their kingdom to its former glory someday. Tattling the statue with Tippi suggests that, though she has long since passed, Squirpina continues to watch over her son.
Squirpina is referred to as Mommy by Squirps. She is also depicted on the walls of the first 25 rooms of the Flopside Pit of 100 Trials, alongside the fourth Pure Heart and surrounded by multiple copies of Squirps.