Thintha, Outcasted Rebel

Whenever another creature you control dies
or becomes the target of a spell or ability an
opponent controls, create a 2/2 black Shadow
creature token.
{1}{b}{b}, Sacrifice any number of Shadows
you control: Return target creature card from
your graveyard to the battlefield with power
equal to or less than the total power of
Shadows sacrificed this way. Put a haste
counter on it.