this myth comes from the fact that snakes heads and bodies can and often will continue to twitch after death. This story usually comes up when a snake is decapitated or clubbed and people claim that the snake only died when sunset / sunrise. ppl have been killed by decapitating a venomous snake, putting the head in a breast pocket and then the nervous twitch causes the snake to seemingly be alive and bite the victim.
(chickens can run around for a while after decapitation, but here are dead due to the severance of the cerbeal cortex to the brain. sounds flashy!!! but i got it from re-animator)
In the kingdom of the blind, the one eyed man is king