Gengar

Evolve Haunter {b}{b} ({b}{b}, Exile a Haunter you
control: Put this card onto the battlefield from your
hand. Gengar gets X +1/+1 counters, where X is the
exiled creatures power. Evolve only as a sorcery.)
Ghost spells you cast cost {1} less to cast.
Other Ghost creatures you control get +1/+1.
Deathtouch