So... he wants... a cthulu planetouched... yeah... not an easy one to do.

I can do it though, if anyone else would like to, I'll step back and off.

For starters... I would give it a 25% crit immunity (Like light fortification).
A -2 Charisma (Horrid Appearance).

A -2 Constitution (incorrect anatomy).

A simple gaze attack causing the recipient to be shaken while in its presence. with a dc of... say... 14+charisma mod.

Perhaps an additional limb, or eye... I usually run this kind of thing as a customizable race with different variable physical characteristics, since no two should ever be exactly alike.

So... roll 1d6...
1: Additional Eye: (roll 1d2) Dark and Lowlight Vision, or eye beam (Roll against beholder eye based attacks).
2: Additional Limbs: roll 1d3, 1 is legs (Always in pairs), 2 is arms(Roll 1d2), 3 is combination of the two (Roll 1d4).
3: Additional sense: roll 1d6, tremor 30, blindsense 20, blindsight 10.
4: Maladjusted Vocals: sonic attack dealing 1d4 sonic, fort 14+Charisma or deaf for 1d3 rounds.
5: Eye Stalks: roll 1d4 for number of eye stalks, each stalk deals 1d3 damage of one of the following: fire, cold, lightning.
6: Natural Weapons: roll 1d4: tentacle, claws, bite, or slam.

You get the jist.