Quark appears in the 1989 film, getting their mail and bringing it in the house. He is later seen hearing the now shrunken kids whistling and tries to go and help them, but is chased away by Spike, the Thompsons' cat. He also accidentally messes up one of Wayne's attempts to find them. He is later seen at the end, finding and bringing them inside along the way, overcoming his fear of Spike. He managed to save Nick from being eaten from Wayne by biting Wayne's ankle. When they are returned to normal size, he celebrates Thanksgiving with them and is seen eating an enlarged bone.
Quark regularly appeared on the show. Originally, he was portrayed as a border collie. However, in the episode "Honey, it's Quarkzilla", Quark mutates into a giant creature, after having eaten some mutant tomatoes created by Wayne. After being returned to normal, Quark becomes a completely different breed of dog.