Snakes are venomous reptiles that kill by biting their prey and injecting them with poison. Snakes can still bite for up to an hour even after death because of a biting reflex.
A Chinese chef died after being bitten by the severed head of a snake while preparing Cobra soup. The fast acting venom of the cobra killed him before he could receive treatment.
After snakes die, they still retain certain reflexes for some time. This is one reason to be cautious even when around a dead snake.