I've been having these for a long time but I can't for the life of me figure out what they are exactly. I suspect they must have something to do with tubeworms or polychaete in general.
What I see is little bunches of tiny (2-5 millimetres in lenght, around 1mm or less in diameter) white tubes, which are no longer attached to anything, i.e. they are lying dead on the sandbed or - more frequently - LR
. They seem to disappear and re-appear in cycles. I never see them in any other fashion, meaning they are not, or I assume they're not, for example, dead spirographs or something. If it helps, they are always slightly bent.
I couldn't find a pic online that matches these things and I'm currently unable to provide one of my own. Ideas?