Good or bad?

[Zodia]

Hello everyone. I'm new to reefing and recently found this on the side of my glass.

I did some searching already and can't find too many reaources on it.

It is a tubless worm and has a feather duster like tip to it. It's capable of moving and does quite often.

Anyone have some more information about them? Should I be worried or are they a beneficial creature.

Thank you.

 

[Lionfish Lair]

I wouldn't worry about that at all.

Could it be a little synaptidae cucumber? I'm not sure the ratio of tentacles to body is correct, though.....