Weird Eyeball

{2}{x}: Eye see you, look through your opponents
hand and library. Take 1 card from their graveyard
or library and put it in your hand(mark it with a
retina counter so you know whose card is whose). X=
half the cost of the card you took(rounded down). If
you do not take a card, return a card from your graveyard into your hand and scry 3.