Appa, Aang's Companion is a uncommon Legendary Creature — Bison Ally card from Avatar: The Last Airbender Eternal (TLE), collector number 268. Current market price: $0.27, TCGplayer market prices via Scryfall.
Flying (This creature can't be blocked except by creatures with flying or reach.) Whenever Appa attacks, another target attacking creature without flying gains flying until end of turn.