TARDIS Bay (WHO-601)

The first spell you cast during each of your turns with mana value 2 or greater has cascade. (When you cast that spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
When chaos ensues, gain control of target artifact. Then planeswalk.