LONG stripy tentacles protruding from rock?

[UncommonSense]

I was looking at @RobertK ’s live rock holding tank with him yesterday when he spotted these extremely long tentacles coming from a piece of KP aquatics rock:

There appear to be multiple of these organisms, with one pair of red/brown, and white striped tentacles per-organism… the large one’s pair of tentacles are very long (3”+), but only maybe 1mm wide at most…

It was a challenge to get a good photo of, so I took a video to try showing feeding behavior:

My best guess so far is Mesochaetopterus rogeri … thoughts?

 

[hatfielj]

Some sort of spaghetti worm would be my guess. They are harmless. I was going to say digitate hydroids, but they are usually whiter in color and look more like stringy bottle brushes, although I guess there could be different species.