If there were a man's silhouette in my bathroom when I was half-asleep, I would have punched it in the head. Or possibly kicked it in the balls. And then my prankster would have been sad to have her cutout bashed! I think you showed great restraint.

You could stand him up in the backseat of her car, like a creepy stalker waiting for work time....

It sounds like your mom's lessons in computer were LOOOONG overdue! Hopefully she will have more fun with it, which will mean less showing up uninvited. ;)