Wanderwine Prophets is a mythic Creature — Merfolk Wizard card from Special Guests (SPG), collector number 132. Current market price: $11.77 (foil $11.19), TCGplayer market prices via Scryfall.
Champion a Merfolk (When this enters, sacrifice it unless you exile another Merfolk you control. When this leaves the battlefield, that card returns to the battlefield.) Whenever this creature deals combat damage to a player, you may sacrifice a Merfolk. If you do, take an extra turn after this one.