Lochmere Serpent is a rare Creature — Serpent card from Throne of Eldraine Promos (PELD), collector number 195p. Current market price: $0.37 (foil $0.50), TCGplayer market prices via Scryfall.
Flash {U}, Sacrifice an Island: This creature can't be blocked this turn. {B}, Sacrifice a Swamp: You gain 1 life and draw a card. {U}{B}: Exile five target cards from an opponent's graveyard. Return this card from your graveyard to your hand. Activate only as a sorcery.