See Challenge # 099. This is what the name "Regenesis" suggests to me.

In utterly vanilla circumstances, this is just half a Ghostly Flicker. It can kill tokens like a Flicker effect can, but a normal creature card just gets flickered by this card. But, if anything at all has modified its power - be it an Aura, some Equipment, a +1/+1 or -1/-1 counter, an Anthem, Exalted, or many other possibilities - then suddenly this isn't returning that same creature. Of course, it might return something else.

This would be more easily phrased if the spell was an X spell. But for XC you can get Disembowel, which will normally be quite a lot better than the X-spell version of this. Except when using this on yourself, of course.

Anyway, it's a pretty odd effect, but ought to be ripe for someone to convert to a different colour or card type. Looking just at the rules text here I'm not sure is the most natural location for it, but when coupled with the name "Regenesis" I can't see it in any other colours.

Ooh, very interesting. You're right, the wording is a bit fiddly, but I can't think of anything much clearer. I like the possibilities.

And yes, it works reasonably well as GU "regenesis", but there should be a good black or white version.

It looks like you can choose a number you don't have any of in play to get a cheap Rise from the Grave. Is that deliberate or a bug, it seems it would be too good and somewhat confusing.

Am I right that this functions as removal against Blightsteel Colossus but not Emrakul, the Aeons Torn? That's a bit confusing, but we probably have to live with it; it's cool it can do that at all.

Oops. Yes, that wasn't meant to be a cheap Zombify. I should add "if he or she did".

And, yes, it does happen to remove a Darksteel Colossus permanently, through a quirk of that thing's wording.