<prompt> Immediate stiffness postmoem occurs in -Cadaveric rigidityCadaveric spasmRigor moisAlgor mois  <response>: Immediate rigor occurs in cadaveric spasm which is contraction of muscles during life which become stiff and rigid immediately after death. Dr. Narayana Reddys Synopsis of Forensic Medicine Toxicology 27 th edition pg. 81. 