Parasomnia refers to a category of sleep that includes the following conditions which can occur at any age of sleep:
Non-rapid eye movement (NREM) parasomnias
Restless leg syndrome and other limb movements
Sleep related eating disorder
REM sleep behavior disorder
Recurrent isolated sleep paralysis
Parasomnias are often genetic but can also be related to brain disorders. They may also be triggered by other sleeping disorders such as obstructive sleep apnea, and by various medications.
The occasional parasomnia episode is probably nothing to be concerned about but if these become excessive or cause harm to yourself or others, then you should consult a physician immediately. Your physician may have you complete a sleep study to help diagnose any abnormalities that may be attributing to the condition.