While the scarab Is a common and very well-known symbol from Ancient Egypt, the deity represented by it, Khepri/Khepera, is less well known in his guise of a scarab-faced humanoid god. To modern eyes this particular combination can seem even more incongruous than that of a jackal-head or lion-face on otherwise human shoulders.
As with all the gods, there are many layers of significance and symbolism associated with him. A good site to read more about this form of the Sun god is:
https://henadology.wordpress.com/theology/netjeru/khepri/