When I come up with character concepts it is typically in a fashion that the character themselves know what they are training towards and has a fairly good concept of what abilities they will attain. Dragon Disciple characters are a slight exception as I'm sure they know that their dragon bloodline is becoming more pronounced but might not know the extent to which it will manifest. Along those lines I was thinking what if the concept for the character was that they intended to further themselves as a successful adventurer but didn't know or even understand what the changes were that were happening to them. I don't just mean they don't know what feats or spells they are gaining access to. I mean overt things, obvious things... things that people can easily see by simply looking at them.
My first thoughts go towards Alchemist. They have discoveries that change their body in instantly apparent, permanent, visible ways. I'm thinking of discoveries like Chameleon, Deadly Excretions, preserve organs, Mummification, Vestigial arm, Parasitic Twin, Phantom Limb, Tumor Familiar, Tentacle and Wings. Instead of the Alchemist actively studying these discoveries and purposefully applying them they could just... happen. He wakes up one day and "Ope... guess there is a tentacle coming out of my side there. That is weird, never noticed that lump on my shoulder wink at me before. Hm... shoulder blades are a little itchy, must be those feathers that are sprouting out of my back now. Wait... what the hell?!"
I like the idea of the character growing claws from his otherwise normal hands. Just because... "I dunno, I guess I just have claws now for some reason. Maybe something I ate? Must be my highly carnivorous diet did it. You know what? I'm just going to not worry about it. This is fine. I'm sure no one will notice."
Claws can be obtained several ways but I like Ranger or Shifter most. Shifter grants some fun options for this kind of concept too. I think I would like these things not activating consciously for the character but operating as a sort of defense mechanism or adaptation thing. Like if the character is having trouble seeing at night, "Oh... ok. I guess I can see in darkness with no problem now? That is handy. I feel kinda like a bat. Wonder if I can... *trips a pit trap, sprouts wings and starts flapping around* ... yep. I guess I'm sort of a bat now. Huh... guess my voice is coming out as squeeks to them now?"
The Wolverine aspect really interests me here as there are some interesting Rage Powers that could add to this. Animal Fury is one of them along with it's follow up Rage Powers. Lesser Fiend Totem is another to gain a gore attack.
Some other things that could go in this toolbox:
Hunter: I like the idea of an animal companionless Hunter so that you can use your Animal Focus on yourself. The ones that add to skills are competence bonuses so they do not stack with those granted by Shifter and are often the same exact bonus anyway. But you can have two different ones active at a time. For this I particularly like the Feral Hunter. Another option would be to use Primal Companion hunter and use Evolutions on yourself instead of Animal Foci.
Ranger: If I were to go with Wild Hunter Ranger I could get Claws via Combat Style and Animal Focus by second level for a couple of minutes per day. Less appealing would be the Shapeshifter which would give Claws via the forced Combat Style and at 3rd level a few options for abilities that stack with most things as they are untyped (with Bear being the notable exception as an enhancement bonus to Str). Also, these are polymorph affects which don't stack with anything the Shifter does.
Anyone have anything else I could add to the toolbox here? Things that alter the character permanently are preferable but also some things that give temporary buffs like that of the Hunter and Shifter are also interesting. I'd love a way to get Evolutions to the character permanently but I do not know of a way to do so besides Synthesist and that isn't adding it to the character, it is wearing it's Eidolon.
What else could help with this concept? Items and equipment? Spells? Feats? Races? Would being a Human with Racial Heritage open up any avenues for fun mutations?
I imagine playing an eidolon (and its human 'friend') would give you plenty of opportunities for this. There's the aspect class feature for the friend to share in the experience a little later.
Vigilantes come in varieties with physical changes in vigilante identity. Agathiel or mutated defender perhaps.
I had a concept for a 20th level mega evil psychic who out of guilt wiped his entire memory.
Using the amnesiac archetype of course. He gradually remembered his powers as time went on.
On feats - Possessed hand and its successors may not have physical changes, but they're visible, appropriate and useful regardless.
One level of oozemorph and suddenly you're a puddle.
You know, I didn't think of the Possessed Hand feats for this build. I have that all setup for another build, though.
Racial heritage Ogre and grab the feat Vestigial Head. It's hilarious, you literally grow a second head. Also you can take the Corrupted flesh feat that gives you the stench abilty and implies that you have some deformity or vestigial limb that has turned fetid and necrotic. I find these feats effective and they add a lot of flavour too.
LOL!