Red and gray bristle worm?

[The_Skrimp]

I have a bristleworm coming out of an empty hermit crab shell. It has a red head with a gray body. Any ideas if that’s is a fire worm? Or just an ordinary bristle worm?

 

[The_Skrimp]

 

[SHNICI]

Hi, it's a bristle worm. For some bad, for the rest good CUC.
Just don't touch it by hands, because you can left with many stinging bristles in. Feeding on detritus and decaying/leftover foot.