Leibniz, Inventor of Calculus

{t}: Exile a nonland card from your hand face down.
{b},{t}: Mill 3 cards, then you may reveal a card
exiled with Leibniz. If you do, return all cards with
the same name from your graveyard to your hand.

Whenever you cast a spell, you may reveal a card
exiled with Leibniz that has the same name. If you
do, copy that spell twice, then put both those cards
into your graveyard.