Reap

Oracle Text

Return up to X target cards from your graveyard to your hand, where X is the number of black permanents target opponent controls as you cast this spell.

Card Rulings

4/1/2008 This card has received errata so that it now targets a specific opponent.
4/1/2008 The count of the number of black permanents the targeted opponent controls is done during announcement since it only affects target selection. It does not get recounted later.