What is this?

[cactusreef]

This neuron looking thing has been here for a month or so. It was cleaned off and then came right back. Any idea what this is?

Ignore the cyano in the background it’s a new tank and I’m dealing with it.

 

[Tahoe61]

Bryozoan, perhaps Hydroid, algae? It's an odd one.

Perhaps
@ISpeakForTheSeas

 

[cactusreef]

It looks like it gets coated with sand. Or maybe coats itself with sand??

 

[Tahoe61]

It looks like it gets coated with sand. Or maybe coats itself with sand??

Spionid looks similar, but hey I am justing guessing.

https://www.reef2reef.com/ams/guide-to-common-hitchhikers-in-reef-tanks.861/