Treva, the Renewer is a rare Legendary Creature — Dragon card from Invasion (INV), collector number 280. Current market price: $1.74 (foil $80.00), TCGplayer market prices via Scryfall.
Flying Whenever Treva deals combat damage to a player, you may pay {2}{W}. If you do, choose a color, then you gain 1 life for each permanent of that color.