What?

[rookie 220]

I have never seen this before today and any help with id this cruel would be very helpful
Came up out of rock and then curled back over itself and went back in same hole
These were the best pics I could get before going back in hole

 

[blaxsun]

Absolutely no idea, but it's the stuff that nightmares are made of...

 

[Anemone_Fanatic]

This is a new one for me. I can't help you ID this one, but I'd suggest removing it when it next shows up.

 

[rookie 220]

Might just pull the rock and put in sump and see if it comes out for a better look

 

[Sleeping Giant]

octopus???

 

[bluemon]

Looks like some sort of Spionid worm.

The two tentacles give it away. I think most try to build some sort of house with sand and rocks, but I think there are some that just live in rocks.