Psionic Devils?

[Kae'Yoss]

what if a psion is implanted?

That's the hidden cheat code, and you'll get a prismatic slaad.

 

[Vraille Darkfang]

Right...so if an arcane caster gets implanted by a red you get a green slaad
normally its a blue.

what if a psion is implanted?

Monster of the Mind (Green Ronin) has the Spectral Slaad, which come about just as you describe.

Very good Psionic Monster Book (if its still in print).

Its based off the Psionics Handbook, but has a Free Webupdate to the Revised Expanded Psionics Handbook.

Edit: This appears to be the 2nd time I'm hocking this in this thread. But the books well worth it for anyone who uses Psionics to any degree in a campaign.