The Forgotten Keeper of Time

Hexproof, This spell can't be countered
{6}: Exile target planeswalker
If this card becomes a creature, you win the game
Crew 6, Put your library into your graveyard
I have seen centuries of turmoil. When I am released,
Bolas will seize to have ever existed. And there won't
have been such a thing as a "spark." My gifts will not
be treated this way much longer.