From harmless moon jellyfish to the deadly box jellyfish and the enormous lion's mane, we're ranking some of the world's most ...

Close up of a irukandji, a poisonous and dangerous box jellyfish from Ningaloo Reef, Western Australia© Anna LoFi/Shutterstock.com One minute, you're swimming in the sparkling water off the Queensland ...

Map of jellyfish sample collection in Singapore, showing where the new species was found as well as where C. indrasaksajiae was spotted for the first time in Singapore. Finding highly venomous box ...

Sperm transfer in Copula sivickisi. The male (above) produces and transfers a spermatophore while grasping the female by the tentacles; the female (below) receives the spermatophore. Box jellyfish are ...