Bristleworm or fireworm! If you want to remove you can they appear probably because you are overfeeding the tank! There are many removal ideas that come to mind. 1- You can get a wrasse as I know a large amount of them eat them. 2- I think arrow crabs also eat them. 3- Some put a shrimp in panty hose on the sandbed overnight and they get stuck to them then you just pull out and throw away. 4- Manual removal with tweezers. I am sure there are other removal processes but nothing else is coming to my mind the second.
I would personally leave them alone and feed your tank less food as they are only supported based on the food supply and when that shrinks so does the population of these worms. If you see one getting longer than 4 or so inches then I would get that one out!
It's a Bristle Worm. Harmless scavenger and a great member of our CUC.
But if you really want to get him out, there are commercial traps or DIY traps. Just google for suggestions as there are several
Personally I'd leave it alone. My tank wouldn't be half as clean without them.