Bloodcurdler is a rare Creature — Horror card from Odyssey (ODY), collector number 116. Current market price: $0.34 (foil $2.18), TCGplayer market prices via Scryfall.
Flying At the beginning of your upkeep, mill a card. Threshold — As long as there are seven or more cards in your graveyard, this creature gets +1/+1 and has "At the beginning of your end step, exile two cards from your graveyard."