Francine's aunt's chameleon

Francine's Aunt's Chameleon was a chameleon owned by Francine's unnamed aunt. It appeared only in the episode Sick as a Dog. When Arthur told his friends that Pal was sick and going to the vet, Francine told them about her aunt's pet chameleon. According to Francine, it escaped its cage, camoflauged, escaped through an air vent, and was never seen again. Ironically, it immediately passed by them (without any of them seeing).