7 Amazing Facts About Jellyfish, the Aliens of the Ocean

From the mild to the absolutely deadly, jellyfish use nematocysts to inject venom into their prey (and unsuspecting swimmers).

YouTube channel SmarterEveryDay teamed up with toxinologist Jamie Seymour of Australia's James Cook University to capture incredible footage of a nematocyst in action.

The box jellyfish has one of the deadliest stings in the entire world. National Geographic reports that the toxins in a box jelly sting "attack the heart, nervous system, and skin cells."

In fact, the shock from being stung by a box jelly is so intense that people have died from drowning and heart failure before they were able to make it to shore.

There are over 1,000 species of jellyfish, with some being "longer than a blue whale," and "others barely larger than a grain of sand," according to the Smithsonian.

Would you ever eat a jellyfish? While it might seem unappetizing in the Western world, in parts of Asia, people have been eating jellies for several centuries.

Australian broadcasting network SBS reports that typically, jellyfish is consumed "in a salad, cold, or pickled." Some restaurants around the world also have jellyfish on their menus for the adventurous eater who wants to try something different.

The Larder in New Zealand has jellies on its menu and some restaurants in Australia also offer the creature as a meal.

SBS notes that jellies taste "a bit salty" with texture that's between what you get from a cucumber and noodles, but "not as gelatinous as you might expect."

The immortal jellyfish has the incredible ability to return to the polyp phase when under threat or duress.

Once it's in the polyp phase, the immortal jelly develops buds and re-releases "medusae that are genetically identical to the injured adult," thus being reborn, according to the American Museum of Natural History.

A couple thousand jellyfish were sent to outer space in 1991 aboard the Columbia to study the effects of weightlessness on the polyps that were sent into orbit.

The polyps and juvenile jellies reproduced to the point that there were some 60,000 creatures floating through space. Interestingly, the astro jellies, as The Atlantic refers to them, had trouble acclimating to life on Earth—mainly gravity—once they were out of orbit.

Crystal jellyfish have green fluorescent protein (GFP) in their bodies that has been used by scientists to track and study the proliferation of diseases like HIV, Alzheimer's, and breast cancer.

Three scientists—Osamu Shimomura, Roger Y. Tsien, and Martin Chalfie—won the Nobel Prize in Chemistry for their GFP research in 2008.

Jellyfish still have the ability to sting even after they've died. In 2010, pieces of a dead lion's mane jellyfish remained in the water of a New Hampshire beach and managed to sting around 150 people.

Most of the massive jelly had been removed from the water but some tentacles with active nematocysts were still floating around. Nematocysts can remain active for 3-4 days after a jelly has died, making a nuisance even after death.