Also from PFK;
Common name: Bobbit worm
Scientific name: Eunice aphroditois (Pallas, 1788)
Origin: Indo Pacific and Western Central Atlantic.
Size: Around 100cm/39", but potentially as large as 3m/10'.
Diet: Lives in soft substrates with its head protruding and feeds on live fish which it detects using a number of sensory antennae on its head. Prey and grabbed in its powerful jaws and then the worm rapidly retreats into its burrow to consume the prey.
Notes: Said to breed at a size of just 10cm/4", which is very early given the size and age of larger specimens. It has an protrusible proboscis, rather like that of the native British ragworm.
Some claim that there may be several related species masquerading under the scientific name Eunice aphroditois, including E. tentaculata.