Story not mine unless I say so otherwise.
When I was about six I was in the bathroom of my grandma's house playing "Bloody Mary" with my slightly older cousins. We were sitting on the floor in a circle. The only thing behind me was a wall and when they were doing the chant, I placed my hand on the ground to use as leverage to scoot myself in the corner for protection. When I did that, I touched a bare foot that was directly behind me. It felt like it was actually coming directly out of the wall. I screamed for someone to turn on the light and when they did, there was nothing there. Everyone's shoes were on so it couldn't have been one of our feet.