Quote Originally Posted by Sipex View Post
Well, one of my problems is I have problems making monsters similar to him. I usually make them too ridiculous to be threatening so I needed some sort of place to start.

I like the anphimorphous black shadow blob with an eye and shadow tentacles idea. Simple, creepy, and threatening.

edit: Hm, there's a lot to this. Glad to hear :)
Read Temple of Tharizdun, especially the part about the Black Cyst in the bottom. Sometimes, the biggest threat from T is existential and not in the form of a monster. Sometimes, it's just the urging for people to be themselves and go after what they want with the lifting of inhibitions.

Remember, nothing is scarier.

As for specific monsters, remember that most monsters aren't going to want to cooperate with that guy. They kind of like existing, so T and cultists would either have to have a front that is more palatable, or flat out lie to potential followers. Abominations of the nastiest sort are possibilities, but generally, any monster that revels in destruction for the sake of destruction, who seeks no dominion, who wants to utterly annihilate everything, are the key there.