Wikipedia
Karkotaka
In Indian mythology, Karkotaka was a naga king, who bit Nala at the request of Indra, transforming Nala into a twisted and ugly shape. Karkotaka had deceived Narada who cursed him due to which he could not move a step. Karkotaka was friend of Nala and suggested Nala to go to Rituparna, king of Ayodhya and stay there under a changed name Bahuka.