in egyptian mythology, nehebkau (also spelled nehebu-kau, and neheb ka) guarded the entrance to duat, the egyptian underworld. he was made up of ka and ba, the two parts of the soul. he is pictured as a snake with two heads. atum was said to have to keep his finger on nehebkau to keep him from being out of control. since he was a snake, he was believed to heal those bitten by snakes and/or scorpions.