Does this count as healing?
No, this is setting life.
What happens if I cast this when I'm at death's door?
You can cast it, and your opponent will go to 0 life, being put at Death's Door and becoming immune to damage for the rest of the turn. You will still remain at 0 life since you can't gain life once you're at death's door.
For purposes of cards that care about the mana cost of spells, what is the mana cost of a spell with X?
If you cast the spell, the mana cost is X. For example, if you cast it for 2 , then Immortal Throne would see it as a 2 . But, if aren't casting the and it's simply in your , , etc., then X is 0 until actually cast it.
Market
$1.58
Low
$0.95
Median
$1.62
