Appa tattoo means meekness and loyalty. Appa, the mount and partner of Aang, is a flying Buffalo, and can always help Aang and others at critical moments. Appa has a simple and honest personality and a gentle temper. It is said that Air Nomad learned the skill of controlling Air from Appa.
Appa has an arrow mark on his head, which is very similar to Aang. He has six legs. According to Aang, there are foot excrement and bugs on his toes. Sokka cleaned it in Episode 9 of the first season. The tail is wide and flat, suitable for flying.