This observation refers to the larger aquatic snail with the greenish shell. Found in a shallow river, this snail seems to have another, smaller snail attached to its shell, in addition to many smaller egg-like things.
Here is a video of it moving: https://www.youtube.com/watch?v=eqJPTRh3IRA
The smaller snail: https://www.inaturalist.org/observations/2166257
The egg-like things: https://www.inaturalist.org/observations/2166286
For aquatic animals, I put them in a plastic bag with water for ease of picture-taking. They were released.