Enter the Avatar State is a uncommon Instant — Lesson card from Avatar: The Last Airbender (TLA), collector number 18. Current market price: $0.32 (foil $0.34), TCGplayer market prices via Scryfall.
Until end of turn, target creature you control becomes an Avatar in addition to its other types and gains flying, first strike, lifelink, and hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)