Chalice of Nothingness

{t}: Add {b}{b} to your mana pool.
Sacrifice Chalice of Nothingness:
Add {b} to your mana pool. If this mana is
used to cast a mono-colored Black creature,
it costs {2} less and gains Haste.
And he drank so deeply from the cup of
nothing, but the dark tasted sweet upon his lips.