Shriekmaw is a uncommon Creature — Elemental card from Commander 2015 (C15), collector number 137. Current market price: $0.28, TCGplayer market prices via Scryfall.
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.) When this creature enters, destroy target nonartifact, nonblack creature. Evoke {1}{B} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)