The mites that cause scabies are tiny parasites, smaller than a pinhead. They are usually picked up by direct skin-to-skin contact with someone who already has scabies, and only very rarely from objects such as clothing or bedding.
The most memorable and emotionally powerful dreams happen during the REM (rapid-eye movement) phase of sleep, which is the stage of sleep when our brains are most similar to a wakeful state.
Normal sleep contains periods of REM (rapid eye movement-dream sleep) during which the brain stem inhibits, or turns off, the motor neurons in our spinal column, preventing any movement except for the eyes. Normally, this only occurs during dream sleep. The apparent reason for sleep paralysis is our safety.