Reverted Fates

For each {w} used to cast this spell, each player
puts the top card of their library into their
graveyard. For each {b} used to cast this spell,
each player puts up to one card of your choice
from graveyard on the bottom of their library.
Each player returns the top card of their
graveyard to their hand. They lose life equal to
its converted mana cost.
Exile each player's graveyard.