Adam Clarke on 1 Samuel 19:13

Michal took an image - את התרפים eth hatteraphim, the teraphim. The Hebrew word appears to mean any kind of image, in any kind of form, as a representative of some reality. Here it must have been something in the human form; because it was intended to represent a man lying in bed indisposed.

A pillow of goats' hair - Perhaps she formed the appearance of a sick man's head muffled up by this pillow or bag of goats' hair. So I think the original might be understood. The goats' hair was merely accidental; unless we could suppose that it was designed to represent the hair of David's head, which is not improbable.