Super Not-Cosmo is the name that the people of Dimmsdale gave Cosmo when he was seen saving Poof using his magical abilities. When they asked Cosmo who he was, he responded "Not Cosmo", causing Chet Ubetcha and the other people of Dimmsdale to believe that to be his real superhero name.
Description
Cosmo's costume was put together while he plummeted between two tall buildings and hit various clothing lines, causing him to appear in blue pajamas with a red cape.
Trying to help Wanda, Cosmo stops by changing Poof's diaper for a wolf and a electric walruse, and then, destroyng the Turner's House.So Wanda threw him out of there, and he got mad about it and went to Dimmsdale Park with Poof.
There he accidentally materializes a whale to play seesaw with Poof, causing it to fly away, because of the the whale's weight.
Cosmo then flies to save his son, and passing through a clothesline, a pajamas, and over that, an underpant, end up in his body.Cosmo then got Poof before he hits the floor, saving him, but Chet Ubetcha was watching that all.So he asked Cosmo's name, that, to don't reveal the fairies existence, couldn't think in anything samrther to answer than "I'm not Cosmo".So Chet Ubetcha started calling him Super Not-Cosmo, creating the alter-ego. He also has a hide-out directly inside Timmy's bathroom which he calls The Super Not Cosmo Secret Lair.