surprisingly, crushing doesn't always kill it. they are so resilient that they will survive w/o an intact shell and will breed even after you unsuccessfully crushed one. I've seen this multiple times in my tank, and even after manual removal, they still persist. once they get going, they can't be stopped lol. they will hide out in your filter, in your substrate, outside of the tank under your tank lid. the best thing you can do if you don't want to deal with pest snails is to remove them immediately upon seeing one in your tank. prevention is the best way to have a snail-less planted tank. it is possible.
it is the Physa genus of snails if anyone is curious.
I trained my fish to attack falling crush snails. And they rip pieces from th falling bodies.