Gastly

Flying, undying
Curse {ut} Pay 3 life. Remove a +1/+1 counter
from another target creature.
Whenever another creature you control leaves the battlefield, opponnents loses 1 life, you gain 1 life.
Evolve {2}{b}{b}{t} Sacrifice Gastly. Search your
hand and library for a card named "Haunter" and
place it on the battlefield tapped.