Fire and water don't normally mix but the ocean is full of living things that put on stunning firework displays. In a sparkling episode of Naked Oceans we celebrate Guy Fawkes night and Diwali as we go in search of some of the many marine animals that make their own light to hide, attack, escape, and woo. Chatting with ocean bioluminescence expert, Edie Widder, we find out about how and why so many ocean species emit light and how twinkling lights are being used to help track pollution through the seas. We also take our pick of the oceans' top 5 firework makers, including snails that glow like a green light bulb, squid that disappear before your eyes, and glowing seas that can be seen from space. And in Critter of the Month, underwater photographer Brian Skerry chooses a super-intelligent hunter.