Nuribotoke are a type of frightening and mischievous yokai that can rise when a butsudan is left open during the hours of night.
In Japanese tradition, a butsudan is a family shrine and is left open during the day but is expected to be closed at night in case spirits from the other world use it to enter our own. The nuribotoke is one such creature.
They will cause mischief, similar to poltergeists, during the hours of night but do not harm humans beyond frightening them.