Random generator gave me Mountain and Death Grasp. Mountain color shifts Death Grasp red. I took the easy way out; Instead of trying to figure out how red can gain life, I just pointed the damage back at the opponent. Subtlety isn't very red, anyway.

I do find comments in Gatherer to be kind of funny sometimes. Death Grasp has a rating of 4.38, and there are no negative comments about it. Despite that, the most popular comment is someone who thinks they need to defend Death Grasp. As if the spell is bad. You shouldn't have to defend something that most everyone likes... I don't think there are as many Super Spikes in the world as the Super Spikes would lead you to believe...

I agree red lifegain would be pretty odd. This is pretty cool as a scalable Searing Blaze / Shower of Sparks / Lunge effect; but I wonder if the feel of Death Grasp might have have been more closely preserved in a Blaze that also does something with the X. Making X 1/1 Goblins, perhaps? A Goblin Offensive that burns for X as well?

That's reasonable, and I might come back to this one. Goblin Offensive might force the card to cost too much to be reasonable, but even +X/+0 may have made sense. Still, the flavor seems a bit odd. In order to invoke the flavor, you want to take life away from an opponent, and give it to something else. But that isn't the flavor of red. Red just wants to hit you, then hit you, then hit you. None of this judo crud.

I like Alex's proposed suggestions, but I also think the card is good as-is: it's obviously an exciting effect, and "damage to opponent" is about as appropriate for red lifegain as you'll find :)

Alternate way for red to gain life:

Any player may have ~ deal X damage to him or her. If no one does, gain X life.

I like what the ray is currently doing now, but I can't help but smile at the idea of red Browbeating its way into some life...

Another possibility would be a haste X/1; that's somewhere between "damage to target" and goblin spray. I also like the browbeat option, perhaps as "deals X damage to target creature or player unless..." although the life gain would probably have to be twice times to make it a decent choice.