Weird thing on green polyp

[triggerfish36]

Hello, I was wondering if someone could identify this (where red arrow is pointing on picture). At first I thought it was some sort of sweeper tentacle, but the weird thing is that it seems to crawl on other adjacent live rock, *detached from the original colony *completely, then returns to the polyp colony. Interestingly, though its tips are significantly longer than the polyps, its ends are the same color green, and the ends contain zooxanthellae. Any idea what this is and what relation it has to the green star polyps themselves? I thought maybe it was some sort of pest or hitchhiker.

35 gallon reef containing soft corals (gorgonia, mushrooms, Kenya tree, toadstool, pink tip anemone, green star polyps, and elephant ear). Otherwise everything is healthy and parameters are in acceptable ranges. Thank you.

 

[ISpeakForTheSeas]

Any chance you could get pics of it under white light (preferably when it's not on the coral that it blends in with)?

Your description sounds like it may be a nudibranch feeding off of the coral, but I can't say for sure from the pic.

 

[triggerfish36]

Thanks so much for the reply. After further inspection, it was a montipora eating nudibranch. I eradicated it.