The Meep is a rare Legendary Creature — Alien card from Secret Lair Drop (SLD), collector number 1581. Current market price: $29.54 (foil $37.38), TCGplayer market prices via Scryfall.
Ward—Pay 3 life. Whenever The Meep attacks, you may sacrifice another creature. If you do, creatures you control have base power and toughness X/X until end of turn, where X is the sacrificed creature's mana value.