When Raylan begins this process, there will be nothing to indicate anything strange or suspicious, nothing unusual at all. But as he begins drawing the spiral, there is the sense of... something. Not exactly a presence but certainly an awareness — to be precise, something other is aware of him.

When he finishes the spiral, he will be overcome by a fleeting feeling of vertigo, accompanied by the visual hallucination of the mirror being covered with such spirals — and the knowledge that they were each of them drawn by him. The vertigo and hallucination fade after a few seconds and the blood on the mirror will be gone. Anyone witnessing this will be unable to explain what happened; one second, the bloody spiral was there, and the next it vanished.

Attempts at repeating this experiment will not have the same results. That sense of awareness is still there, but the vertigo and hallucinations will not occur again for Raylan or at all for anyone else, and the blood will remain on the mirror (though it will vanish once everyone has left the room).