Is this just a normal bristle worm?

[Deep Dive Aquatics]

Hello everyone, saw two of these guys on my rockwork and pulled them out of my tank. If you could believe after I got some photos and videos they started to fight and one got bit or ripped in half. Crazy

 

[Sharkbait19]

Looks more like a dorvilleidae worm - harmless

 

[Deep Dive Aquatics]

Looks more like a dorvilleidae worm - harmless

Thank you! What I thought was a split is likely just poop because they look more transparent now. They seem to swim a bit by wiggling around but do seem to have legs if you noticed. Thank you again for the help anyone else confirming it would be appreciated.