Described as "a friendly monster" in the initial draft of the screenplay, the character of Fizzgig is the pet of Kira: resembling a dog in voice and manners, but unlike a dog in that his facial features are tiny and his entire body is represented by a brown/red/gray ball of fur. Fizzgig moves by rolling, though he does appear to have at least two legs. His mouth, when open, appears to encompass most of his size and possesses two sets of sharp teeth. He is fiercely loyal to Kira, has an aggressive temper, and is wary of unfamiliar things. Fizzgig is at first wary of Jen, but becomes his friend.

Fizzgig later made a cameo in the Fraggle Rock episode "Gobo's Discovery", as one of the background cave creatures.

Fizzgig was designed by Brian Froud and his design and fabrication supervisor was Rollie Krewson.