What is on my snail?
Sorry for the blurry photos. I had a hard time getting my camera to focus when shooting at an angle through the tank's glass.
I have two mystery snails in my tank and have had them for several months now, along with several fish. When I got the snails, I was told to monitor for eggs to avoid a population outbreak, so I've been scanning the waterline and surfaces carefully when doing my water changes. Today, I noticed this round, black shape attached to my snail that is seemingly preventing it from retracting back into the shell. At first, I thought it was a baby snail that got missed in one of my scans, but I don't see its head anywhere. I do see a disc-like shape that looks like it could be an operculum, but I'm not sure. My fiancée pulled the snail out of the water briefly earlier today to check if it was alive, and it did move, and she said the black shape was soft to the touch, unlike a snail shell. What could it be?