Scary looking worm

[Toisoljer]

This worm has built it's own little cave pulling small corals and bits of shells around it. It has quite the chompers on it as I've seen it grab bits of shells and move them. I thought at first it was a bristleworm but it has a head like a catapillar? Does anyone know what this is, and if it is reef safe?

 

[greenbean36191]

It is a bristleworm, just not one from the family most people recognize as bristleworms. It's a eunicid. Most of them are harmless scavengers, but some of of the larger species will eat corals and some people even report them going after small fish. They're super fast and hard to catch though, so unless you see it causing a problem I wouldn't bother trying to remove it.