A Hunting Horror.

Hunting Horrors resemble enormous ropy, black serpents or worms with bat-like or umbrella-like wings. Their forms are said to continually shift and change, twitching and writhing, so that it is hard to view them. Some may have only a single large wing rather than two.

These beings are dispelled by daylight, though a strong enough burst of light could sear one to dust. Hunting Horrors move swiftly and serve as harriers for the god Nyarlathotep. One of Nyarlathotep's avatars, the Haunter of the Dark, shares similar traits with the Hunting Horrors.