Morph as a function of regeneration?

[Waldschatten]

I've been trying to figure out how to create a character that uses their regeneration to fuel morphing ability.

The character has the ability to change cosmetic appearance as well as take on other nonhuman qualities such as fangs, claws, fur, a tail, thickened skin (low levels of DR like running on rocks without damaging bare feet), and the like.

Morph, on its own, doesn't seem right for them though.

The ability takes hours, or even days for large changes, of slowly altering their form to accomplish. Definitely not a combat advantage, they aren't going to be growing claws for combat and then removing them once the fight is over.

Changing minor cosmetic features to evade facial recognition would be accomplished in a relatively short period of time, larger survivability advantages would take more time to accomplish.

In typical play this would be primarily a disguise advantage, though in wilderness settings it could have more valuable benefits.

Thanks for any insight you can provide as to how this would be written into a character.