Jellyfish are known for drifting to and fro at the whim of ocean currents—but not all species are so passive. The millions of golden jellyfish that pack Palau’s Jellyfish Lake spend much of ...

umbrella-shaped jellyfish. The sea creature — which was first spotted in 2002 in a deep-sea volcanic structure in ocean waters south of Tokyo, Japan — has a bright red "X" on its stomach.

Despite their often dangerous stings, these creatures create serene scenes as they float through the deep sea Jellyfish are among the planet’s simplest creatures, made up of about 95 percent ...

Anyone unfamiliar with the biology of the venomous Portuguese man-of-war would likely mistake it for a jellyfish. Not only is it not a jellyfish, it's not even an "it," but a "they." The ...