The detaching head. The second form of the rokurokubi tradition: the neck does not stretch at all, and instead the head lifts away from the sleeping body and travels on its own until morning. Both forms usually go under the single name rokurokubi.
Notes
Rokurokubi, the Long-Necked WomanThe long-necked woman of Japanese legend: ordinary by daylight, a neck that leaves her collar by night. The name is younger than you would expect.
The Oldest Rokurokubi Story Is About a HeadThe 1677 tale published under that name has no stretching neck in it at all. A head leaves its body, travels the roads at night, and laughs at a traveller.
Volume
Japanese Horror Folktales Collection
ROKUROKUBI
Tales of the Floating Head Yokai
Fifteen Japanese tales of strange heads and impossible necks — and of what people do after seeing them.