The Faceless Witch

This spell cannot be countered.

You may sacrifice any number of creatures when
you cast this spell. For every creature that you
sacrifice in this way, this spell costs {1} less to cast.

Whenever you sacrifice a creature scry X, then all opponents lose X life, where X equals the creatures converted mana cost minus one.
The Faceless Witchs toughness is equal to the
number of creature cards in your graveyard.