Sorry it is the best picture I could get. Does this seem like possibly a baby stomatella snail or something else? It is DEFINITELY a snail as I can see a tiny little shell . Only reason I’m guessing stomatella is it seemed at first like a little slug crawling its way up the glass.
I do have several limpets but as it moved it was more oblong like a snail so I don’t think so. And now it has fallen or let go of the glass so I can’t get anymore pictures until it shows itself again