It would also work with adrenaline as well, I'd think, as well as freezing or delay.
Would it also copy damage taken, buff effects (chaos power, blessing), and that sort of thing as well?
I like the idea, btw. I was thinking at first that it might be overcosted, but 4//3 might actually be about right. It should cost less than twin universe, I'd think, but probably should cost more than most buffs. You might still be able to get away with dropping the cost by 1 on each version. It's hard to say right off what kind of impact this would have on the game. If it turns out to not be that game-changing, 3//2 would be fine; if it does, it should stay 4//3. Right now most of the uses I can think of for it are mostly funny or casual decks.