Oaken Siren is a common Artifact Creature — Siren Pirate card from The Lost Caverns of Ixalan (LCI), collector number 66. Current market price: $0.20 (foil $0.25), TCGplayer market prices via Scryfall.
Flying, vigilance {T}: Add {U}. Spend this mana only to cast an artifact spell or activate an ability of an artifact source.