I was examining the snails in my locality when I realized that some of their mucus trails, even on smooth surfaces like glass, have slight irregularities a few dozens of microns high. I put these under my compound microscope, and found that they were little microscopic nematodes!
After an internet search, I was able to conclude that these worms are a species belonging to the genus Phasmarhabditis, whose members are parasites of terrestrial gastropods, like slugs and snails. These parasites only begin reproducing once the snail dies, and feed on the bacteria that grow on the rotting carcasses.
To test this theory, I took a few snail corpses which had begun to decompose in 35mm culture plates and added a few worms. Within a few days, the worm population skyrocketed and I was able to differentiate larval and adult worms.
I then used the foldscope to view these worms as the Foldscope 2.0 allows for amazing oblique illumination effects when using diffused sunlight as a means of illumination. I've attached a few pictures and videos of the worms below.

The distinctive curved posterior end of the nematode leads me to believe that this species of worm belongs to the species Phasmarhabditis eagyptica, which was discovered as recently as September 2023 in Egypt. As yet, there have been no reported findings in India - however, based on morphology only, I think it may be. Phylogenetic studies will have to be conducted to support or reject this prediction.
Can anyone in the community help identify this? Here are some videos as well:

In the second video, I was able to capture a little worm larva too!