Voyage to the sea floor: expedition returns with fascinating finds

Museum Victoria collects gelatinous fish, spiny crabs, scarlet sea-spiders, nightmarish cookie cutter sharks and plenty of rubbish

" Gallery: Deep sea discoveries: sea pigs, a dumbo octopus and glow-in-the-dark sharks

There's no sunlight four kilometres below the waves but there is light.

It comes from a sea cucumber that emits a faint glow from its sticky skin, attracting fish and crabs that try to take bites out of its side. The skin is both a lure and a trap, marking incautious predators with a sticky glowing dot, an "eat me" sign to any passing larger predators.