Whispering Specter

Oracle Text

Flying

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Whenever Whispering Specter deals combat damage to a player, you may sacrifice it. If you do, that player discards a card for each poison counter he or she has.

Card Rulings

6/1/2011 You choose whether or not to sacrifice Whispering Specter, and the number of poison counters the player has is counted, when the triggered ability resolves.