Corpse Lunge and Boneyard Wurm

[Jason]

Corpse Lunge:
Instant
As an additional cost to cast Corpse Lunge, exile a creature card from your graveyard.
Corpse Lunge deals damage equal to the exiled card's power to target creature.

Boneyard Wurm:
Creature — Wurm (*/*)
Boneyard Wurm's power and toughness are each equal to the number of creature cards in your graveyard.

This came up today. Say I have a Boneyard Wurm and three other creatures in my graveyard. When I cast Corpse Lunge, exiling Boneyard Wurm as part of the cost, does Corpse Lunge deal 3 or 4 damage?

[Ryoku]

Since the Wurm is exiled as part of the cost for the spell, it will not be in your graveyard at the resolution of the spell. Thus, it will not count itself when checking its power and toughness.

[cdr]

A spell or ability that needs to know information about a card will look at that card where that card is expected to be when the spell/ability resolves. In the case of Corpse Lunge, the card was exiled as a cost, so it will be expected to be in the exiled zone, and that's where Corpse Lunge will look at its power (it even says "the exiled card's power").

In the case that the card is no longer in the expected zone (the Wurm somehow became un-exiled between announcement and resolution), the last known information of the card when it was in the expected zone is used.

Replacement effects can modify the expected zone. If there were a card that said something silly like "whenever you would exile a card from your graveyard, instead that card remains in your graveyard", the expected zone for the Wurm would be the graveyard after you play Corpse Lunge.