Random generator gave me Ancestor's Chosen and Flames of the Blood Hand. There's a lot of open black common slots, and I would have preferred slipping this card in there, but this ability is too useful for Mashup: the Gathering. There's a strong life gain theme among the commons, and I wouldn't want to subvert whole decks with one common creature. Besides... answer cards seem tacky in common, unless you got a good reason for it, or it's an answer to a very common problem (My opponent is attacking with creatures! How dare he!).

Oh, also, I was a bit concerned that if both players had a copy of this card then the world would explode. But both cards just tell the other player that they can't gain life. I'm pretty sure this isn't infinite loop time.... I might have to adjust the wording... not sure.

If an opponent would gain life, you gain that life instead.

I think that works? And if both players have it, it would be an infinite loop that can't be ended.

I agree. That reads much better. Thank you.

As for the infinite loop... yeah. I'm going to pretend it doesn't exist for now. That certainly could come up in a draft, but it's not something you can intentionally create yourself, without playing around with Bazaar Traders or something. It is a problem, though.

No, it wouldn't be an infinite loop. No more so than Furnace of Rath makes Shock deal infinite damage. Each replacement effect gets to apply once to an event. If after all replacement effects have applied it ends up back the way it was, that's fine. If both players have this, lifegain ends up affecting whichever of these two players it would have originally affected.

Well, my mind is at ease. I would have hated having to solve this card.