Gerrard's Hourglass Pendant is a rare Legendary Artifact card from Dominaria United Commander (DMC), collector number 17. Current market price: $2.06, TCGplayer market prices via Scryfall.
Flash If a player would begin an extra turn, that player skips that turn instead. {4}, {T}, Exile Gerrard's Hourglass Pendant: Return to the battlefield tapped all artifact, creature, enchantment, and land cards in your graveyard that were put there from the battlefield this turn.