Shleeps are one of the most recurring NiGHTS enemies, appearing in both NiGHTS into Dreams and NiGHTS: Journey of Dreams and Christmas NiGHTS into Dreams, they also made minor appearances in the NiGHTS Archie comics.
Outside of NiGHTS, Shleeps made a cameo appearance in Sonic Pinball Party and Sonic & All-Stars Racing Transformed.
In NiGHTS into dreams, they can only inflate themselfs and act as obstacles to NiGHTS, however NiGHTS still can easily defeat them by using his drill dash.
In NiGHTS journey of dreams, they will surround themselves with their wool and if NiGHTS comes in contact, their wool will slow him down, but it won't cause damage.
In the NiGHTS Archie Comics a Shleep was able to make Claris fall asleep by spraying a yellow dust in her face.
- Shleep and Mamu were the first enemies to appear in a NiGHTS game, Shleep if the players starts NiGHTS into Dreams with Spring Valley and Mamu if the players starts with Splash Garden.
- Curiously, Shleep didn't appear when the third level Nightmarens attacked Nightopia in NiGHTS: Flying through the Sky Without Wings, but it did make a cameo as an icon and when the Nightmarens were introduced.
- Shleeps are the only third level nightmarens from NiGHTS into Dreams who reappeared in NiGHTS: Journey of Dreams.
- In NiGHTS: Journey of Dreams, the Shleep Mepians may sleep and snore sometimes in My Dream.
- It's name is a combination of the words "sheep" and "sleep".