Flying (This creature can't be blocked except by creatures with flying or reach.)
At the beginning of your upkeep,
mill (To mill a card, a player puts the top card of their library into their graveyard.) a card.
Threshold — As long as seven or more cards are in your graveyard, Bloodcurdler gets +1/+1 and has "At the beginning of your end step, exile two cards from your graveyard."