Plagues of giant jellyfish are floating towards Japan - billions of these Sumo-sized gelatinous creatures will wreak havoc on Japan's coastal towns and cities. The Giant Nomura Jellyfish - over 2 meters wide and up to 200 kilos, are one of the world's largest jellyfish. Global warming has seen an increase in their numbers - and this year Japan will see the biggest bloom yet. These jellyfish are destroying everything in their path and with no known natural predator, the populations are continuing to rise. Watch as fisherman and scientists work together to try and understand why millions of these giant jellyfish are washing up on Japan’s shores and why, a once every 40 year phenomenon, is now happening annually.