You've got the semblance of a good idea, but it's not great in it's current form. The idea of a near-invincible monster that becomes more powerful every time you try to damage it it pretty ridiculous.
If I were you, I'd have the summoning costs at 5
/4
, give it starting stats of 2/4 for both versions and have it the active skill:
Inversion: 3
For 1 turn, any changes to health affect attack instead.
This way, it's got a nice (but not OP) synergy with chaos power, and it doesn't make it indestructible. If the skill isn't activated, then i can be killed just like anything else, and if it is, then heavy CC can make its attack go negative. Note that instakills (devour, shockwave+congeal) will kill it even with the skill active.
Also, with the card you're suggesting, 1 rage elixir gives you an 18/7 creature for a grand total of 9 quanta. Add to that a liquid shadow, and it's now also a vampire gaining 1 attack every turn. This beast is also immune to all CC except rewind, freeze and delay. This is beyond ridiculous.