Volatile Hex

Choose any target. You may discard a card.
When you do, this spell deals X damage to that permanent or player, where X is the discarded
card's mana value.

(as a hex resolves, an opponent of your choice shuffles it into their library face up instead of
you putting it into your graveyard. If this card would leave a library other than its owner's, its owner exiles it instead and may cast it for as
long as it remains exiled.)