I have snail looking things growing on inside glass of fish tank.?

I have a 10 gallon fish tank with mollies and platos and a zebra fish. A few days ago I noticed what looks like snails growing on the glass. I did a partial water change, and vacuumed the gravel and removed everything from the glass. This was less than a week ago. This morning I noticed them on the glass again. Some are black and some are white. I have live and plastic plants and a cave. I’m pretty new to this, so any help would be greatly appreciated.