Anybody know what this is?

[xx0505xx]

Hey guys,

I'm new to the saltwater hobby and just started up my first JBJ 45 gallon tank. Upon buying the tank and cycling / curing the rocks I came upon this worm looking thing. Just as an FYI the rocks I purchased were pukani from BRS.

Here's a picture of it. It only comes out in the dark and never come out above the surface of the sand. Should I get rid of it? or is it a beneficial worm?

 

[SeaCucumberFan]

All worms are beneficial, except eucinid worms

 

[xx0505xx]

All worms are beneficial, except eucinid worms

ok but do you know what kind of worm this is?