I saw a video in which a decapitated snake head still tried to bite.
I also saw a video in which a man was hit by the moving tail of a dead crocodile.
So why do reptiles move even after death?
In warm-blooded animals, our high metabolisms are a significant disadvantage when being decapitated. Just a few minutes without oxygen and a mammal's brain is caput—the result of a massive cascading cellular die-off. Not so with cold-blooded reptiles. Their slow metabolism sustains their internal organs for far longer than a mammals causing them to completely die far more slowly. Essentially, cutting off their heads only makes them "mostly dead".
Reptiles stimulate impulses after death due to reasons, lets see snake for example. Snake after been crushed still moves because of the electrically charged ion in the nerve calls of snake, as the brain continuously send messages through the nerve cells, note that the brain of snake need the least amount of oxygen for survival so does not die as quick as you may think, the brain can still live for about 1hr after the body of the snake stopped stimulating impulses. Be advised, never put your finger in a Dead snake's mouth as it can still harm.