Did I see a bristle worm? or a potential serpent of death?

[saltwater]

I heard fireworms are pretty destructive but trying to search the net I get all kinds of answers. If I could find him I guess I could count antennae, measure it's thoracid anticompilative region and compare it to it's carbuncle diamater to determine type of polychaete I have encountered. Wait just let me get my flux capacitor and ionic phase inducer to measure... Needless to say I got a little lost way before the protective satae.
This is why I appreciate everyone's help. I wonder if they make a "marine worms for dummies(me)" book.

[Diana]

If you had a flux capacator you could go back in time and get the sucker when he was small.

I always try and get rid of the bristle worms, especially when they get that big. It usually involves gloves and tweezers.... and a stiff drink.