Appa is a beloved character from the animated series "Avatar: The Last Airbender." He is a flying bison and serves as the loyal companion and primary mode of transportation for Aang, the series' protagonist and the last Airbender. Appa is characterized by his massive size, white fur, six legs, and distinctive arrow markings on his head and back. Despite his imposing appearance, he has a gentle and affectionate personality, especially towards Aang and the rest of Team Avatar. Throughout the series, Appa's bond with Aang is portrayed as deep and unbreakable, highlighting themes of friendship and loyalty.