Samus Aran, Galactic Hunter

Flash, first strike
When Samus Aran enters the battlefield, put a bounty counter on target creature that dealt damage to you this turn.
{x}{r}{r}, {t}: Samus Aran deals X damage to target creature. If that creature has a bounty counter, she deals damage to that creature equal
to twice of X instead. Shuffle Samus into
your library.