Sleepers

quote from mr.zamboni:Sleepers in broad terms are just beings that only reveal their true forms in certain times at certain places.

There is also a subclass of sleepers which are still called sleepers but they're diffrent. These sleepers only show there sillouhete but nothing else. One monster in this class is shambrock

One of mr.zamboni's monsters is a sleeper named Beyon likely being based on the word beyond as his body is beyond our imagination.https://www.youtube.com/watch?v=ZhtIs1Qz6BI