Treacherous Vampire

Treacherous Vampire

Creature - Vampire | Power/Toughness: 4 / 4 (CMC 5)
Flying
Whenever Treacherous Vampire attacks or blocks, sacrifice it unless you exile a card from your graveyard.
Threshold -- As long as seven or more cards are in your graveyard, Treacherous Vampire gets +2/+2 and has "When Treacherous Vampire dies, you lose 6 life."