Voidvelg Requiem

Ace (You can also cast this spell by sending 2 Black Galaxy creatures you control to the Graveyard)

You can send the top card of your library to
the Graveyard, this creature gains +2/+1 for each other Black Galaxy creature you control (max 2) until the end if the turn. Then, if an opponent controls a creature with White in it's color identity, this creature gains an additional +4/+2 until the end of the turn.