Thanos, Mad Titan

Vigilance, menace
When Thanos, Mad Titan enters the battlefield,
you may have it fight another target creature.
(Each deals damage equal to its power to the other.)
{t}, Sacrifice a creature: Search your library for
an artifact card with converted mana cost X or
less, where X the sacrificed creature's
converted mana cost. Reveal it and put it into
your hand. Then shuffle your library.