Kitten

Kitten is Gunter's offspring, first seen in "The Chamber of Frozen Blades." It appears to be magical in some way, as when it hatches, it is glowing and floating, and it has a heart-like symbol on its forehead. It also has a tail that could be mistaken as a 5th leg. The kitten's father is unknown. Doctor Princess said that the birth was "horrifyingly beautiful."

Trivia

 * The character is referred to as "Kitten" 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 a Ice King/penguin offspring, which they thought would be a "cool, gross-out moment." However, the network vetoed that idea, and it went back to being a kitten.