Common Boomslang (Dispholidus typus), juvenile, defensive display, family Colubridae, South Africa
This is a rear-fanged Colubrid snake, that is actually highly venomous, very dangerous to humans.
The famous herpetologist Karl Schmidt died from a Boomslang (a juvenile, no less) bite in 1957. He did not think that a rear-fanged snake could deliver a deadly bite.
(In his defense, most herpetologists at that time concurred with this assumption.)
Most rear-fanged snakes are not seriously injurious to humans.
photograph by WVZ Nature & Wildlife Photography