How This Jellyfish Can Hurt People Without Even Touching Them

If you think about jellyfish stings, then you’d probably imagine just swimming at the beach and minding your own business before getting stung by an unsuspecting jellyfish tentacle that just managed to get a little too close to your leg for your own (and the jellyfish’s) liking.

But did you know that some types of jellyfish can sting you without even touching you or getting near? Enter the upside-down jellyfish, which can sting you by excreting, well, snot into the water (you know what, getting stung via tentacle doesn’t sound so bad now).

Jellyfish Snot

So-called for its default position where it rests bell-up on the sea floor, this jellyfish species (Cassiopea xamachana) can usually be found in some coastal areas, especially near mangroves since forests of these can grow in warm coastal areas and let saltwater bathe its tree trunks and roots.

According to the research's findings, which were published February 13 in the scientific journal Communications Biology, this jellyfish species usually sting others by releasing a type of mucus that has stinging cells inside it. Called nematocysts, these cells typically show up on jellyfish tentacles, although this one managed to find a new way to disseminate them and catch some fish (and unsuspecting people) off guard.

Per the researchers, this new study is the first to ever explain why swimming near them upside-down jellies can cause our skin to feel prickly, or provide a burning sensation.

As per Cheryl Ames, a marine biologist at Tohoku University in Sendai, Japan, the stinging cells found in the mucus can blob around in a lab dish, “zooming around like a Roomba [vacuum] zapping brine shrimp.” Her team observed brine shrimp becoming paralyzed shortly after touching a cassiosome. Shortly afterward, the animals unfortunately died.

According to the findings, these jellyfish types can usually be found resting on the ocean floor in groups, which then lets photosynthetic algae that live on their tissues create the nutrients needed to benefit them both. As for the snot, the scientists are unsure why they do it. Per theories, it might be used to help catch prey, or simply fend off predators.

Jellyfish A compass jellyfish (Chrysaora hysoscella) moving in open water, on may 26, 2016 in Marseille, France. Alexis Rosenfeld/Getty Images