Bristleworm/ Fireworm (Chloeia parva) by Samantha Craven
Bristleworms are Polychaetes (marine Annelid worms). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. To touch is to pain. They can also release the bristles into the water, so you can even get stung in the general vicinity. 

Bristleworm/ Fireworm (Chloeia parva) by Samantha Craven

Bristleworms are Polychaetes (marine Annelid worms). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. To touch is to pain. They can also release the bristles into the water, so you can even get stung in the general vicinity.