Shark Tonic Immobility
Tonic immobility is a natural state of paralysis which animals enter, often called animal hypnosis. Its function is not certain. It may be related to mating in certain animals like sharks. It may also be a way of avoiding or deterring predators (playing dead is called thanatosis).
Tonic immobility has also been used for the paralysis which often immobilizes animals, such as rodents or birds when they feel threatened by a predator. Tonic immobility plays a role in survival if it helps a hunted animal to blend in with its surroundings.