So I don't practice anything like this for practical reasons, however I did find this particular topic interesting with relation to Bloody Mary and Sandman when I one day learned about the Scrying Glass. As a kid I wasn't willing to try it in the bathroom mirror in the dark. However, as an adult(I still wouldn't try it) I don't think it would work anyway in a standard mirror and that is a good thing.

Source: https://www.pinterest.com/pin/323977766927506487/

This documentary was the wildest one, because it supposedly shows you how to use a scrying mirror properly which 90% of the videos I saw did not explain rituals.

Even if this is a total fake, I can see where at a certain point optical illusion combined with self hypnosis might produce a result in the mirror.

So I ask you now.......who is willing to build a REAL Scrying mirror and conduct a real ritual to see what happens instead of Hollywood theatrics. ;)