What the heck is THIS

[ZzyzxRiver]

It looks like a poop. But way bigger than anything my fish could make (about a centimeter long?)
It doesn’t appear to be alive but I honestly can’t tell if it’s moving with the water or because it’s actually moving. A nassarius snail just climbed onto it too.

 

[tbrown]

Snail operculum.

I think I spelled it right. Basically the "trap door" the use to seal themselves in. Probably off of a turbo snail.

 

[tbrown]

I'm fairly certain that's it.

 

[ZzyzxRiver]

It’s definitely not an operculum, because it’s not a hard disc, it’s more of a gooey tube shape wrapped around itself. I can see how the picture sort of looks like that though. I’d take another picture but it’s being totally devoured by the nassarius snail. So definitely not operculum.