Illithid worm? 3.5

[Rezby]

I'm trying to find this but I'm failing horribly at my search check. Its this illithid (mind flayer) tadpole that never got implanted into a host, and instead grew to monsterous worm size, and its described as this tragic creature and all that - I'm trying to find out what its called and what book its from. Any help would be much appreciated.

EDIT: The neothilid from the XPH. I fail at looking. Disregard this thread.

[hamishspence]

They're called Neothelids, are in Expanded Psionics Handbook (and the SRD).

Unimplanted tadpoles that are a bit too large to implant, but haven't yet grown to Neothelid size, are in Complete Psionic.

EDIT: Swordsaged by the original poster.