Slate, Cosmic Theorist

At the beginning of your upkeep, look at the top
card of your library. You may put it into your graveyard.

Whenever you draw a card, if it’s the second card
you’ve drawn this turn, you may exile the top card
of your library. You may cast it this turn without paying its mana cost.

"The universe is a puzzle waiting to be unraveled
—one piece at a time."