Sleep paralysis is a situation in which a person is awake but unable to move or speak whether waking up or falling asleep. During an episode, a person may hallucinate (hear, feel, or see things that aren't there), usually causing fear. These hallucinations are unofficially called, "Sleep Paralysis Demons." The episodes are usually only a few minutes long. It might be a one-time occurrence or reoccurring.
Sleep Paralysis Yuri (or SPY) is a specified state in which a person under the age of 50 undergoes a more intense transition. The sleep paralysis demons one encounters is consistent and is manifested as a purple-haired Japanese cartoon girl named as "Yuri." Yuri often wields a knife and has irregular behaviors ranging from stabbing and slashing and pleasuring herself unconventionally.
While regular sleep paralysis is mostly harmless, SPY will often affect a person's body and mind. A person undergoing this state would move and jerk their body involuntarily, disturbingly reacting as if the person is being attacked or tampered with. A person would drool saliva and trinkets of blood due to intense movements. The most notable symptom is the sexual arousal on at least half of the people experiencing SPY.
SPY generally last in less than an hour for most people, unlike the usual sleep paralysis that would last under ten minutes. It may be dangerous however, as in the worst case scenario, one would endure SPY in more than 48 hours. Because of how violent and taxing SPY is, a person would expire before five hours pass without constant supervision.