But no, they have all been found - and photographed all just off the English coast.
All the creatures pictured below were found by divers in the North Sea, off Norfolk.
High ferocity: Long-Spined Sea Scorpions change colour to disguise themselves so they can ambush their prey
Beady eyed: Snake Pipefish are related to seahorses and are becoming ever more common in British waters
Claws: Fearless scavengers, Velvet Swimming Crabs are so-called because their shells are covered in tiny bristles
Smile please: Tompot Blenny were believed to be extinct in the North Sea until spotted off Weybourne in 2007. They are rarely over 6in long
Little nippler: A common prawn has ten long legs, some of which have claws. At 2.5in, they can live up for five years
Secrets seas: An adult sea slug sits atop a ship wreck hunting for its favourite food - tiny jelly fish
Fancy that: Delicate Peacock Fanworms filter feed with their retractable feathery tentacles
Sticky fingers: Elegant anemones use their stinging tentacles to trap food
Positively glowing: Just half the size of your little finger, the Lightbulb Sea Squirt uses its glass-like clusters to filter seawater and extract plankton