Appa's mother

The Mother Sky Bison is the Flying Bison that gave birth to Appa and about 9 other Flying Bison. She lived at the Eastern Air Temple and is probably a great mother.

Flashback
In a flashback it shows Baby Appa with his siblings flying around the mother sky bison's head. The mother is shown to be extremely big when compared to her young. The baby bison were less than one tenth of the mothers size and when Aang and Appa first met Aang was already slightly shorter than Appa. She likely died with all the other Flying Bison during the Air Nomad Genocide. It is also noted that her right horn is slightly cut off from the top, most likely to differentiate her character design from Appa himself.