Phantom Flyer [Golem]

Only fragments of the phantom flyer can be seen: shimmering dark wings spanning 20 feet, something like a horse's back, and two black tentacles of similar length. It belongs to the night and must vanish before the sun rises.

In torchlight or dimmer conditions it is 90% undetectable. By day it must shelter in a shadow, any shadow, underfoot or beneath a cart or table, where it looks like an unusually deep patch of black. Hidden this way it cannot attack or fly, but it can flow through connected shadows at its flying speed. Only truesight reveals it then, though detecting for magic shows a faint aura.

As strong as any iron golem, it lashes with both tentacles each round for 2d8 damage apiece. It is harmed only by +3 or better weapons and is unaffected by fire or cold spells. Any light spell that succeeds against it pinpoints its position. Darkness heals it: 1d8 hit points from darkness, 2d8+1 from continual darkness.

Swift and silent, it flies as fast as most dragons, can carry two equipped man-sized riders, and can lift a draft horse with its tentacles. That makes it an ideal messenger and spy. A wizard might have it ride the shadow of an adventurer's warhorse all day, then whistle it home at dusk to repeat every word it overheard. Next he may fly out on its back or send it to snatch one of the party for some sinister purpose at his tower.

Its master is whoever holds the silver whistle, itself faintly magical. Should the whistle go missing, the golem waits in a nearby shadow, destroying light sources and nothing more, until someone sounds it. If the whistle is destroyed, the flyer leaves for the Demiplane of Shadow.

It exists only to serve. Its substance is drawn from the Demiplane of Shadow, and what form its animating force takes there is unknown.

Creation takes a wizard of 18th level or higher three months and 90,000 gp. Two large mirrors face each other squarely, exactly eleven paces apart. Between them lie the pinions of a vrock (a tanar'ri) wrapped twice over in fresh spider silk, with a large chalice of molten silver set before them. The wizard then casts geas, fly, disintegrate, continual darkness, forget, black tentacles and wish. What remains is a reflection made real, along with the whistle that rules it.