Cazinth, Diligent Steward

Nobility {1}{u} (You may cast this spell for its
nobility cost rather than its mana cost if you control
a creature with the greatest converted mana cost.)
When Cazinth, Diligent Steward enters the battlefield, draw a card, then discard a card
unless its nobility cost was paid.
{1}{u}, {t}: Return Cazinth, Diligent Steward to
its owner's hand.