My Chaos trolls kitbashed from Ogre bulls and 40k Nob heads. I wanted to have fat little, pukey hulks running amok in my army. Again, I avoid GW's metals and river trolls aren't Chaos enough for me. No sir, I don't like it.
This 2-headed fellow was inspired by the picture of Chaos trolls from the WoC army book. The troll's skin is goblin green basecoat, Scorpion green "highlights" if you could call them that, then Thraka Green wash. I like the cartoony effect and I may use it for my 40k orks. I am not sure, yet.