A team of scientists investigating a large area of the Pacific Ocean known as the Clarion-Clipperton Zone have found an astonishing 5,000 new species living on the ocean floor. The species they logged include previously undescribed varieties of urchins, starfish and sea cucumbers, as well as ‘gummy squirrels’ and other strange and delightful, transparent invertebrates. But the CCZ is under threat: it has been earmarked for deep-sea mining.