For 10 points, name this scarab-headed god.
In some sources, this god was depicted as a twin-headed snake which  would be tugged by eight people from both ends. According to The Book  of the Dead, the chanting of this god's name is useful in avoiding decay in  the afterlife. Some legends claim that this god was killed every night and  his corpse is dismembered, but at dawn he triumphantly returns. At  Heliopolis, this god was conflated with (*) Atum-Ra, and amulets were  popularly made in honor of this figure. He was said to push the sun across the  sky like a ball of dung. For 10 points, name this scarab-headed god.
In some sources, this god was depicted as a twin-headed snake which  would be tugged by eight people from both ends.
Khepri