The Law of Surprise

{p/b}{p/b}: Prevent damage that would be dealt to
target opponent by a source another opponent
controls. During you next upkeep, that
opponent reveals cards from the top of their
library until he or she reveals a non-land
permanent. Put that card onto the battlefield
under your control. Any player may activate
this ability.
"I claim the law of surprise. That which you
already have but do not know."