Thevil, the Ceaseless Wonder

When Thevil, the Ceaseless Wonder enters the battlefield, each player exiles the top 3 cards of
their library.
Whenever a player casts a creature or sorcery
spell from his or her hand, that player may exile
it. If the player does, he or she may cast another
nonland card exiled with Thevil, the Ceaseless
Wonder without paying that card's mana cost.