Bad ending for Lizards is really bad. I did it after good one, and the difference is petrifiyng. But you can see it only after interacting with characters later.
Roushk can be found back in forgotten temple near the lake. To take him to your prison you need reptile's lure. Always horny and angry/subby. But even that's about "fine", after all we didn't talk much to him before.
Hell starts with Rhot. As he promised, he comes back to ruins and attacks you. With reptile's lure after you defeat him, and usage of corrupted water from the lake, he becomes 100% cursed only because you intentionally put the water as last "touch" on him. He loses himself in curse, loses the ability to speak, becoming a mindless-full-of-instincts hissing lizard.
Probably people who really hate all kind of reptiles would like this ending.