Ancient's Grudge

When a creature you control is exiled or sent to
the graveyard by a spell or ability an opponent
controls, you may discard this card. Ancient's
Grudge can be cast only if it was sent to the
graveyard this way.
Flashback {2}{g}
Target creature gets trample, hexproof, and
+X/+X until end of turn, where X is the
highest converted mana cost among permanents
you control and in your graveyard.