Catalepsy, an abnormal condition in which the body and limbs are stiffened, but movable, and stay in whatever position they are placed. An afflicted person tends to remain in any position in which he or she is placed. Catalepsy may occur in hypnosis and in some mental disturbances. It has sometimes been mistaken for death. In cataplexy, another abnormal muscular condition, the person suddenly goes limp. Cataplexy often follows a strong emotional experience, and may be accompanied by fits of sleep. The name cataplexy is sometimes used as a name for hypnotic sleep.