should be lizard eggs. Cohen thought the twist was what ultimately made the episode both "touching" and "interesting". Producer Ron Hauge came up with the idea of someone shooting a bird and feeling guilty about it. Hauge told the staff a few weeks before Cohen started writing the episode that when he was 13 or 14 years old, he accidentally killed a bird after he got a Wrist Rocket slingshot, and took a shot at a bird that he thought was "far, far away". Hauge said his friends were excited about it, but he was "dying inside". For the scene in which the bird is killed, Cohen received further inspiration from an episode of The Andy Griffith Show entitled "Opie the Birdman". The writers were trying to figure out a way to have Bart kill the bird without actually wanting to kill it, and decided to give the gun a crooked sight that Bart would be unaware of, so when Bart intentionally takes a shot at the right of the bird to avoid it, the bullet still hits the bird. After Bart kills the mother bird, he imagines himself before a bird court with a vulture, an eagle, and a toucan as judges. This sequence was added to "liven up the visuals", because the writers thought the episode tended too heavily towards extreme realism and because most of the scenes in the episode were taking place in and around the Simpsons' house. Then-show runner Mike Scully had done the same thing with an episode he wrote for season seven called "Marge Be Not Proud". In that episode, Bart gets caught shoplifting, and writer Bill Oakley suggested the addition of a fantasy sequence to get away from the realism in the episode. The Family Fun Center the Simpsons visit is based on a real family fun center in Falmouth, Massachusetts that Cohen went to as a child to play video games. The Bolivian tree lizard is a fake species, but Cohen based it on real animals, including the dinosaur species Oviraptor, which was originally thought to eat eggs. The species is also based on the cowbird and the cuckoo, which lay their eggs in other birds' nests, and Draco, a genus of gliding lizards. Cohen also received inspiration from the cane toad that started "taking over" Australia in 1935. "Bart the Mother" marked the last guest appearance of Phil Hartman on