Wall of Mourning is a rare Creature — Wall card from Midnight Hunt Commander (MIC), collector number 48. Current market price: $0.34, TCGplayer market prices via Scryfall.
Defender When this creature enters, exile a card from the top of your library face down for each opponent you have. Coven — At the beginning of your end step, if you control three or more creatures with different powers, put a card exiled with this creature into its owner's hand.