Thank You for Your comments

@ Hombre:
Unfortunately my modelling skills are not good enough to scratchbuild such a model.
But luckily this model is easy to buy and is cheap!

Look for "D&D Large Chaos Beast" on ebay or at your lokal gaming store (near the collectable Miniature Games)
http://shop.ebay.com/i.html?_nkw=large+chaos+beast&_sacat=0&_odkw=Roper&_osacat=0&_trksid=p3286.c0.m270.l1313There are a lot of usefull D&D collectible Miniatures (especially in the "Unhallowed" and the "Underdark" Range). Look for the new "Roper" (perfect Avatar for the great old One Zhar!) and very nice Rat Swarms

But I have to warn You! While these models are belonging to a collectable Miniatures Game, they are made of soft plastic. With the Roper, Chaos Beast and the Rats you have no problems because they are massive enough not to be bend easily. But with Humans and Humanoid Creatures there could be light problems with the legs. (It could happen that the colour goes of due to bending those models).
@B. Basiliscus:
The Worm used to be an "Mage Knight" Creature in earlier Days. There was a limited Range of Metal Minis for Mage Knight.
Maybe you are lucky to find one at ebay, look for "Crypt Worm"
http://cgi.ebay.com/Mage-Knight-Metal-WZK-547-Crypt-Worm-Spawn-Miniature-/120405176260Of course I converted this model lightly. First I used Greenstuff to give it the Eye. This was easy to make due to the size of the upper mouth.
For the wings I used a winged plastic backpack of Games Workshop's Possessed Chaos Space Marine. Just cut away the midel part and glue the wings at the back of the worm. They fit perfectly, so you don't have to correct them with Greenstuff
@ D@rth J@ymZ and Drachenklinge:
Both Creatures will become more slimey. It's the first time for me using water effect for Slime and therefore I started with little parts first.
Especially the One-Eyed Worm has to be redone, making it more slimey.
I like the idea of using gloss-varnish! With this the model will still look slimey but not too slimey. Thanks for this great Idea!

Ongoing Project:
Now I'm going to look for Firearms (Shotguns, Tommy Guns) and things like torches to convert my Westwind Brotherhood into Cultists.
I really really love those monks, they are just Awesome (I think I need some more afterwords for a Gothic Horror Range

)
what to build in detail:
1 Cult leader (eqquipt with a ritual dagger and a unholy artifact)
1 Tommy Gunner
2 with Rifles
1 with a double Barreled Shotgun
And of course I have to remove the crosses

Greetings everyone.