Seeking information on some form of strange creature

Last time I was in the proper, I was almost attacked in the inn by perhaps one of the strangest creatures I have ever seen. I heard someone say it was called an "Illithid", or something along those lines. While its appearance did certainly disturb me, my interest was also sparked. I wish to learn as much as I can about these creatures, and would greatly appreciate it if anyone who knows about these things would be able to find time next moon to teach me more about these.... things.

Captain Arza
White Lotus Trading Company
OOG: Calder Putnam

Describe the appearance of this creature. The name is familiar.

It had tendrils of some sort coming out of it's face. Or what I assume was a face... Aside from that, it looked relatively humanoid

from what i have been told an illithid is a creature with an octupus like face however it has great psionic abilities. I am not that knowlledgable on the topic so I would say if anyone else says different then assume they are right. I am just giving you a basic overview of what I have heard so far.

Those of you who have no first hand experience should refrain from muddying the waters.

Arza - seek me the next time you are in Travance and I will educate you a bit.

Speaking from experience from my time in the Underdark, these are dangerous creatures that you better have a strong will if you ever face one again. It doesn't end well for anyone involved otherwise. It is rare to see one out of the gloom of the Underdark so I hope your interest is merely intellectual. To put it bluntly--there are very few things I have ever seen make dark elf warriors run in fear and an Illithid is one of them.