Mad Snake God
Not much is known about this deity. Doesn't sound good though, huh? Its principal temple is noted for two things. Firstly, it holds a giant ruby that has inspired thieves and Barbarian heroes for generations to go after. Secondly, however, it has the Terrible Man-Eating Sloth of Clup which guards said ruby. Even Crowdie the Strong wasn't up to the task. It is unknown if more well-known heroes have tried the same thing.
There are plenty of snake gods on Roundworld such as Glycon, Ungud and various other such entities as the Nagas of Indian, Thai, and Cambodian folklore. Not many of them are mad though, as such. See here for more.