Dragon Cunning

Riddle 3. When one or more cards are put
into your graveyard this way, Dragon
Cunning deals damage equal to their total
mana value to target player. (To
Riddle X, an opponent looks at the top X
cards of your library and separates them
into a face-up pile and a face-down pile.
Put one pile into your hand and put the
rest into your graveyard.)