Help me build my Psionic Villain

[Trask]

I'm currently running a campaign where I'm beginning to flesh out a villain but I haven't quite yet put pencil to paper on his statblock and I'm looking for some help with that. The concept is that this villain is an ancient Psionic Troglodyte Paragon. My party is currently level 2 almost 3 and I'm thinking to put this villain (his name is Groth) around level 6 or 8 to give the players a decent way to go before actually crossing blades with him but not making him TOO far out of their reach. I've never actually touched the Pathfinder Psionic stuff at all so does anyone have any pointers on some powers that are potentially too overpowered/complete garbage or just some that would make for a good an interesting boss fight? Thanks!

[Trask]

Looking at it more I think I'd like to make him a Psychometabolist, it fits his monstrosity I think as a character.

[Cwymbran-San]

Psychometabolists - or Egoists in PF - are masters of the self-buff. Metamorphosis, Corrosive Aura, Ectoplasmic Form, these can be fun, but your BBEG needs time to manifest them all. So, give him enough minions to stall your party until he is up and running.

Start with Chamaeleon, then let him hide in the shadows of his lair until he is all buffed up.
Use Ectoplasmic Form to let him escape and be the recurring villain we all love to hate. Let him have a power stone for that, so he can escape even when his PP are depleted.
Protect him with Biofeedback and Forced Share Pain.

So many possibilities to make a PC's life miserable, so few rounds to do it...

[Trask]

Oh thats good. I want a nice way for him to get away because I've been playing him off as very smart, I dont think he'd be caught out so easy.