Oh, hey, neat! Do you think this could only cost ? What with it being so similar to Wake the Reflections? Or do you think the fact that you could play this as a 0/1 necessitates the extra ? (And is it important? Would it be better to make it a 0/0 for ?)

This is indeed nifty!

It's better than Wake the Reflections in that it can copy one of your opponent's tokens. Just like Wake the best thing to do with it is use it on a token copy of a good thing (made by Rite of Replication, Séance etc), and this isn't instant speed, so I think this would be fine at 1 mana.

No I'm not sure whether the possibility of noncopy casting is worth the extra mana. If I put it in a file I'd edge my chances with that, though in most random sets this is probably a CMC1 card (unless maybe there's a lot of Wurm tokens running around XD).

Small thingie: if you want this to target, it has to be an ETB triggered ability (and you can't give it 0 toughness). But these effects don't normally target because it's a little counterintuitive (for example, it would not triggered the copied creature's ETB ability).