There’s a Japanese fable that begins with a man waking at 2 a.m. from a sleep poisoned by nightmares: evil visions of entwined snakes, blood-soaked shirts, ears of dogs turned inside out and human voices issuing from pots of rice and the mouths of foxes. “Baku-san,” he cries out, three times, “come eat my dream!” Then he waits, looking out the window at the airless night for a liminal being with the face of a lion, the tusks of an elephant and the body of a horse to come and lay its hooves upon the threshold.
This Baku has been a part of Japanese folklore since at least the 14th century, and is derived from Chinese and Japanese mythology older than that. The chimera’s composite appearance was described differently over time. Sometimes he had scales and spikes, other times he had fur and fangs; often, he had the head of an elephant and the body of a jungle cat. The confusion makes sense — wanting to create a dream-eater that could help men sleep better, God stitched the Baku together from the scraps of other animals.
The Baku's heyday occurred around the 17th century, an era when nighttime visions had great significance. The first dream of the New Year in Japan, for instance, was thought either to portend fortune for the year or, depending on individual beliefs, literally come true. Therefore, it became important to make your first nocturnal experience of the year a good one, and certainly not a nightmare. It was the Baku's job to shovel away dark thoughts and pave the way for prosperity.
You could beckon the beast with your voice, but it was more common to invoke it by drawing its image or writing its name on a piece of paper. Hanging that on the wall or hiding it underneath a pillow was thought to ward off bad dreams.
However he was mustered, the beast was beloved. In the Muromachi period, it appeared in ink paintings hung in the imperial court, on ceremonial amulets exchanged as diplomatic gifts and in gold lettering on the wooden pillows of princes. These days, the Baku appears on prints with other good luck symbols sold at temples and shrines and over the internet. (The Baku is even the basis for the Pokémon Drowzee, so in a way, the ancient power of the creature lingers today in graven images of the animated character, from official toys and trading cards to hypersexual fanart in the deepest corners of the Dark Net.)
The Baku's life wasn’t great. A sleeper would call it, and it would have put disturbing thoughts in its mouth. People assumed it was fine with devouring them. While most of the time the Baku begrudgingly went about its job, it was wise and not always easily controlled. It also didn't suffer fools.
The dreamer in the fable tells the Baku of his nightmare: He is in a dark crypt, hovering above a pale corpse attended by hooded watchmen. He is drawn closer and closer and finds the corpse is his own body, and the corpse opens its eyes (his eyes) and attacks him. The dreamer grabs an axe and hacks the corpse (his corpse) to bloody, pulpy pieces. Awful. But the Baku frowns and disputes the man’s analysis of the dream.
“That is a very lucky dream, a most fortunate dream,” the Baku says. The creature then explains that the dream is a metaphor for the successful exercise of law and order over the wild ego. The man, stuck with this grotesque dream, is disappointed. Disappointed, but not terrified — until he realizes that a hungry Baku doesn't go away if summoned and left starving. It unhinges its lion’s jaw and eats every dream, desire, wish, hope and passion the man has, until he is left an emotionless husk without a soul, purpose or dream to speak of. The Baku bounds away over the rooftops of the city. On those nights, the Baku sleeps very well.