Welcome to Chase Games!
Whenever Thief of Sanity deals combat damage to a player, look at the top three cards of that players library, exile one of them face down, then put the rest into their graveyard. You may look at and cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell.
Company Number: 11263697
26 Market Hall Street, First Floor,
Cannock, Staffs, WS11 1EB