Is this really a hypnosis or just some primal defense system that kicks in, like "snake ahead, freeze". I had a pet python and I know for a fact that snakes will only eat moving food, if you just leave a dead mouse snake will not touch it (same as frogs and many other lizards and amphibians). Pray needs to move to attract the interest. So if you don't want to get eaten by a snake the perfect defense is exactly this, don't move a muscle, stand very still. And many animals have "hard-wired" defense against snakes, for instance like cats get scared by cucumbers and other snake like shapes, although they never seen a snake in their life. Just a wild theory of course, but it might be that?