Appa, Steadfast Guardian

Mana Cost: {2}{W}{W}
Total Cost: 4
Type: Legendary Creature — Bison Ally
Description: Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.
Power: 3
Toughness: 4
Colors: W