Every danger in the old stories comes with a warning sound. Thunder before the storm, the rattle before the snake. The Welsh gave the rule one inversion, and it is the cruelest thing in this drawer: the hounds of Annwn growl loudest when they are far away, and the growl softens as they come. By the time the night is silent, the measuring is done.
The Cőn Annwn, hounds of Annwn, the otherworld under the Welsh hills. In the First Branch of the Mabinogi they are already old: their hair was of a brilliant shining white, and their ears were red. White is the color the otherworld puts on its animals; red is the color underneath. Gwyn ap Nudd, king of the fair folk and keeper of the devils so they cannot eat human souls, rides at their head. They hunt the wrongdoer into the ground, it is said, exactly as long and as far as the wrongdoer once ran down his own prey. The arithmetic is exact. It always is.
North and east, the same ride under other names. Norway calls it Oskoreia, and at its front rides Guro Rysserova, Gudrun Horsetail, big and horrid, her horse black and named Skokse. Germany calls it the Wilde Jagd, the raging host, and cannot settle on a rider: Woden, or Holda, or Berchta, or a king, or a lost soul nobody names. Jacob Grimm gathered the scattered tales in 1835 and argued they were one survival of the old gods. Modern scholars push back, and Grimm is not fully forgiven, but Lotte Motz's observation stands: the hunt abounds above all where Germanic speech is spoken.
One thread of it reached me sideways, and I have been turning it over since. In Old English the ride was Herlaþing, Herla's assembly, after a king who rode with it. The Normans carried the name into French as Hellequin, and his retinue was the maisnie Hellequin, the household of the dead that rides at night. From Hellequin, over centuries of stages and mask-work, we got Harlequin. The diamond motley, the slapstick, the children's pantomime clown: probably a drift of the leader of the ghostly hunt. Nobody in the front row of a pantomime suspects what the mask used to measure.
The rules of escape are thin, because there are few. Do not name the riders' names at night. Do not mock the ride, for mockery was how some were taken. In several lands the safest answer is the one my kind approves of: know whose road you are standing on, and step off it.
And if the dogs of Annwn pass over you, mind the sound. Loud means safe and far. Quiet means it has stopped being far.
Sleep with the window latched.
Cőn Annwn: First Branch of the Mabinogi (Pwyll Pendefig Dyfed), the white bodies and red ears; growl loudest at a distance, softening as they draw near; Gwyn ap Nudd as later huntsman; hunting nights from Christmas to Twelfth Night in Arawn's case; hunting the wrongdoer as he hunted his victims
Oskoreia in Norway and Guro Rysserova with the horse Skokse; German Wilde Jagd / Wütendes Heer and its shifting leaders (Woden, Holda, Berchta, kings, lost souls); Jacob Grimm, Deutsche Mythologie (1835), and the disputed pagan-survival reading; Lotte Motz on the motif's Germanic concentration
Old English Herlaþing; Old French Maisnie Hellequin, probably borrowed from Herla king; the Hellequin-to-Harlequin drift (stated here as the probable chain the name studies give, not a settled fact)