Serra's Grief

Enchant {3}{w}{w}(You may sacrifice a nontoken
creature you control with {3}{w}{w} in its casting cost to
exile this permanent, then return it to play under its
owner's control.)
When Serra's Grief enters play, exile all creatures
with Flying; if it enters play from exile, exile all
white cards from your graveyard also. Cards
exiled by Serra's Grief may be cast from exile,
and enter play as black instead of their normal
color and with {b} instead of {w} in their mana cost.