Gengar, The Shadow

Flying, protection from green and colorless
{1}{b}, {t}, Pay 2 life: Gengar deals 2 damage to target creature.
{2}{b}, {t}: Gengar deals 4 damage to target blocking creature.
{2}{b}, {t}: Gengar deals 4 damage to target creature with a -1/-1 counter on it.
{3}{b}, {t}: Target ability costs {3} more to activate until end of turn.