Amphinomidae, also known as the fireworms, bristle worms or sea mice,[2] are a family of marine polychaetes, many species of which bear chaetae mineralized with carbonate.

[3] The best-known amphinomids are the fireworms, which can cause great pain if their toxin-coated chaetae are touched or trodden on.

[4] Complanine is a quaternary ammonium salt that has been isolated from the marine fireworm Eurythoe complanata.

It causes an inflammatory effect upon contact with the skin or mucous membranes.

It was previously known that handling the fireworm caused it to release a chemical that induces inflammation of the skin of marine predators and mammals (including humans).