Yume no seirei

Yume no seirei (夢の精霊, “dream spirit”), is a mysterious yōkai in Japanese mythology believed to cause nightmares.

He appears in the Hyakkai Zukan, "The Illustrated Volume of a Hundred Demons," created by Sawaki Suushi in 1737.

[citation needed] Yume no seirei is also part of the Bakemonozukushie (化物尽絵, "Illustrated Index of Supernatural Creatures"), housed in the Harry F. Bruning Collection of Japanese Books and Manuscripts of the L. Tom Perry Special Collections, Harold B. Lee Library at Brigham Young University.

Pale clothing with long, flowing sleeves was draped loosely about the seemingly fragile figure, and the head and upper part of the body were strongly delineated.

From the waist down, however, the form was misty and tapered into nothingness.”[2]Baku, or dream-eater, is a benevolent yōkai with the power to eat nightmares.

[4] This threat turns a seemingly innocuous prank into a deadly one and is all the more frightening because of the vulnerable unconscious state of dreaming.