On the Leonie dive at the beginning of January I saw lots of these with Dave and have since noticed them quite a lot. They are collected for food in the aquarium and also for reproductive studies. This study is done back in the UK so they get set back for their gonads to be dissected. They are polychaete worms that live in their casts in the sediment. What you see is their spider web tentacles over the top of everything. To collect them you dig into the sediment and put the handful of sediment and hopefully the worm into the collection bag. It is hard to get a picture of them unfortunately.