Tonic immobility

Tonic immobility is the body remaining temporarily motionless and rigid in the face of an intense threat. This is a state deeper than freezing; the body, as it were, locks, and voluntary movement becomes difficult. Seen in many animals in the wild, this response works as a last form of protection. Tonic immobility is not a voluntary choice; it is an automatic response of the nervous system. This state often resolves slowly after the threat has passed.