It could be a shrimp molt but I’m doubtful. Shrimp molts look like shrimp that are pretending to be ghosts so they’re extremely identifiable. Even if it was ripped in half, you’d likely still be able to tell what it was. That being said, your mystery snail cannot eat a shrimp (or even the molt) whole so it would not poop it out whole. I would say that this is likely a piece of plant matter that has been in the tank for a while but not actually attached to anything to obtain nutrients. This would cause it to turn white and lose some of its shape/structure. Just take it out and toss it 👍
Normansandsphoto2112 
It could be a shrimp molt but I’m doubtful. Shrimp molts look like shrimp that are pretending to be ghosts so they’re extremely identifiable. Even if it was ripped in half, you’d likely still be able to tell what it was. That being said, your mystery snail cannot eat a shrimp (or even the molt) whole so it would not poop it out whole. I would say that this is likely a piece of plant matter that has been in the tank for a while but not actually attached to anything to obtain nutrients. This would cause it to turn white and lose some of its shape/structure. Just take it out and toss it 👍