Another mystery solved - I think

Last December, looking at the limpets on the walls of my aquarium, I noticed a long, worm-like thing wrapped around its neck. I couldn't identify it; nor could my helpful commenters.

Original photo, from "No end to mysteries".

And then, a month later, I posted a second "worm", which turned out, instead to be a limpet's gill.

Limpet gill, from "The mystery deepens", and "One down, one to go"

Since then, I've been watching limpets closely. I've seen the gills many times, but there's still that long neck-scarf "worm" to identify.

I think I've found it!

That's no worm!

I think it's limpet poop!

Do you agree?