It might be very expensive, but it seems OP nevertheless.
For 11
you gain a creature plain better than Phase Dragon (8 attack, but cheaper and with momentum).
That's OP in itself.
You can then fuse it with an opposing dragon to kill it outright and gain a powerful indestructible attacker, or fuse it with your own Otyugh, FFQ, Pharaoh, Flying Eternity, Golem, Deathstalker or any other important creature to gain benefits you'd need 2-3 cards otherwise (though cheaper). Anyway it makes the combo easier to pull off against a FG for example. You could for example play this, then next turn play a flying Eternity and SoR it, then fuse it. A 3 card combo that gives you a pretty damn good win condition. This and Deathstalker - 2 card combo for 4 poison each turn if I'm right. Possibilities to abuse are countless.
This makes it OOOOOOP.
I guess for a card like this 20
should be a minimum. For the upgrade 30 probably.