Corriander, the Hidden

Hexproof
If a creature an opponent controls would cause you to lose the game you may instead exile Corriander
and put that creature on the bottom of its owner's library.
Whenever an opponent casts a spell that targets you, you may pay {w/u}{w/u}{w/u}{w/u}{w/u}{w/u}{w/u}, if you do counter that spell.