Kassadin, Void Walker

Ward {3}, protection from colorless.
Whenever a player casts a spell you get {e}.
{e}: Exile Kassadin, Void Walker, then return it to
the battlefield under its owner's control. Double
the cost of this ability until end of turn.
"Not once have I lost my way. I know exactly where
I am, and how many more paces it would be to the
doom of all things."