Fortuna, Merchant of Wagers

Whenever you exile cards from the top of your library, you may put a land card exiled this way
onto the battlefield tapped.
Whenever you cast a spell from exile, roll a d20.
1-15 | You take damage equal to that card's
mana value. If the card would be put into your graveyard, put it into your hand instead.
16-20 | Copy the spell twice. You may cast the
copies without paying their mana costs.