Dietrich's Sarcophagus

When Dietrich's Sarcophagus enters the battlefield, create two 1/1 black Bat creature
tokens with flying.
{t}: Add {b}{b}
{2}{b},{t}, Sacrifice a Bat creature you control:
Search your library for a Vampire card with
mana value equal to 2 plus the sacrificed
creatures mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.