Rhombic Egg Eater (Dasypeltis scabra)
If threatened it may coil and uncoil, rubbing its roughly-keeled scales to emit a hissing sound, and will strike quite viciously exposing the dark inner lining of the mouth, but it is completely harmless. This behaviour is said to mimic that of the dangerous Saw-scale Vipers of North Africa.
Eggs are swallowed whole into the neck region and then cracked using bony projections below the vertebrate, the shell crushed, the contents swallowed and the remains of the egg shell regurgitated in a neat little package.
This snake is easily confused with the Common Night Adder, but the Common Egg-eater has keeled scales, a vertical pupil and a few V-markings on the head and neck.