I don’t think a Creature of the Night would have Obsessive Compulsive Disorder, but if you look into ancient legends. .
It would lead to the conclusion that they do.
Old legends say, bury the suspected vampire with mustard seeds in his coffin. When he wakes for his nightly wanderings, he will have to stop and count all the seeds before he can leave his coffin. If you didn’t “remember” to add the seeds inside the coffin, you can scatter them around the top of his grave. He will have to gather them and count them.
Fishing net or knotted ropes/cloths will also work, (same idea, the vampire will have to count each knot).
Seems like OCD behavior to me.
Mari Wells 