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No, it's not the title of a trash-horror b-movie but something that happens every years in Japan and is actually happening right now. They are the Nomura's Giant Jellifishes, "Echizen Kurage" for the japanese, (Nemopilema nomurai). They can grow up to 2 meters (6 ft. 7 in.) in diameter and weigh up to 200 kilograms (440 lb.) each. While stings of this large jellyfish are painful, they are not usually toxic enough to cause serious harm in humans. However, the jellyfish's sting has been reported as fatal in some cases by causing a build-up of fluid in the lungs. As a precaution, fisherman encountering these jellyfish wear eye protection and protective clothes. To date there have only been eight reported deaths from the Nomura's sting. However their increasing number is becoming a serious problem for the Japanese Fishermen which more and more often find huge density of these animals, one hundred times higher than normal. Often the weight of the echizen kurage broke the nets or crushed the fish to death; those that survived were poisoned and beslimed by their tentacles.
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(Asahi Shimbun/Tetsuji Asano/AP)