Ice Cream Kitty is, as her name implies, a fragile Mutant cat/ice cream hybrid. She appeared in the second season of the 2012 TV series. She's living in the Turtles' refrigerator as Michelangelo's pet.
She's composed of three prominent flavors: a tiny dab of chocolate, vanilla (which makes up her whole torso) and strawberry that makes up her upper body, but before she got mutated, she was a wounded brown-striped street cat that had appearances in both the foreground and background in several prior episodes. She currently lives in the Turtles' freezer and Mikey uses a portable cooler to carry her around when venturing outside if necessary.
Of Rats and Men - Ice Cream Kitty made her first appearance as a normal cat pouncing on a rat. April saw her and took pity on her, and decided to take her back to the lair. April dropped off Kitty at Donnie's lab, where Mikey was eating ice cream. After Mikey left April's kitty unattended next to a mutagen recipient, where his ice cream fell earlier, the cat licked it and then ice cream kitty was born. Horrified at what had happened and afraid of what could happen to him if caught, Mikey quickly hide Ice Cream Kitty in the Turtle's Freezer. Later, Mikey took Ice Cream Kitty in a cooler and flung her into the Rat King, where she attempted to scratch him.
Pizza Face - Ice Cream Kitty is shown, still residing in the turtles' freezer. After Mikey had finished interrogating one of Pizza Face's goons, he threw it in the freezer with Ice Cream Kitty who instantly horrified the defenseless pizza goon with her unsettling head turn.
In The Invasion Part 2, Mikey packs her up in a portable freezer to take her with him as they try to find a new lair.