Cnidarians

While swarm of jellies may look serene, you're best off keeping your distance. A sting from the most dangerous jellyfish on Earth can be deadly. Even when we're not looking at the most dangerous, many jellyfish species have venomous stings that can cause everything from mild discomfort to serious pain.

By Talon Homer

The life cycle of jellyfish can seem almost otherworldly. Some species are the closer to actual immortality than anything else we see in the animal kingdom!

By Mack Hayden

Most jellyfish are more bothersome than threatening, but the box jellyfish is so poisonous you might not make it out of the water alive.

By John Perritano & Mack Hayden

Sea lice aren't actually lice — they're jellyfish — but they're no fun when they get in your bathing suit.

By Jesslyn Shields

Don't think you have much in common with a jellyfish? What researchers just discovered may surprise you.

By Laurie L. Dove

You're going on vacation to a place where jelly fish stings are a common occurrence and you want to know how to treat a jellyfish sting. This article will tell you how to treat a jellyfish sting.

By HowStuffWorks.com Contributors

As you observe jellyfish twirl underwater, it's difficult not to be mesmerized by their graceful movements. But if their tentacles touch your skin, you'll regret being anywhere near these gelatinous blobs.

By Jennifer Horton

How do coral polyps mere millimeters in length form the world's largest living structures? Will these giants of the sea last much longer if the present rate of destruction continues?

By Jennifer Horton

Although jellyfish have been around for over 650 million years, they're still very mysterious. Learn the all about the fascinating jellyfish life cycle.

By Stephanie Watson