Kitten is Gunter's offspring, first seen in "The Chamber of Frozen Blades" in the Ice Kingdom. It appears to be magical in some way, as when it hatches it is glowing and floating and it also has a heart symbol on its forehead. Doctor Princess said that the birth was "horrifyingly beautiful." In "Princess Monster Wife," Kitten makes a brief appearance as Ice King starts singing to his wife. It is also seen at the end of the song before Ice King reveals his sculpture. In "Reign of Gunters," it plays a major role in assisting the penguins by using its laser vision.
It is a kitten that is completely pink, except for a red heart on its forehead. It has large blue eyes with black pupils. It has pointed ears and a thin tail.
The Kitten can levitate and emanate a yellow aura even while sleeping. It can also focus its aura into explosive bolts of energy, which it uses to break down the Candy Kingdom wall in "Reign of Gunters."
- The character is referred to as "Gunther's love child" in the character design documents.
- In one version of the episode's storyboard, Gunter's offspring was going to be a hybrid Ice King/penguin creature. However, as Adam Muto explained, he originally drew a glowing kitten, but Thurop Van Orman (who was working on the show at the time) wanted it to be an Ice King/Penguin offspring, which they thought would be a "cool gross-out moment." However, the network rejected that idea, and it went back to being a kitten.
- According to Patrick McHale, the kitten appeared in "Princess Monster Wife" because Adam Muto liked the sound of McHale's cat, Arthur, singing along to the demo track for the Ice King's song, and he added the kitten to the episode's storyboards.
- It has been shown to sleep under Ice King's chair, as seen in "Reign of Gunters."
- The character has three stubs on the end of its tail and has the ability to float just like the Lumpy Space People.
- Since it came from an egg, it is oviparous.
- Gunter has the kitten on his back and wears the Demonic Wishing Eye in the Adventure Time Game Creator.
- The Kitten is a boss in Adventure Time: Explore the Dungeon Because I DON’T KNOW!