Kellan, the Kid is a mythic Legendary Creature — Human Faerie Rogue card from Outlaws of Thunder Junction Promos (POTJ), collector number 213p. Current market price: $1.62 (foil $2.56), TCGplayer market prices via Scryfall.
Flying, lifelink Whenever you cast a spell from anywhere other than your hand, you may cast a permanent spell with equal or lesser mana value from your hand without paying its mana cost. If you don't, you may put a land card from your hand onto the battlefield.