Jellyfish are immortal invertebrates that look like a transparent mushroom floating gracefully but with tentacles and the secret recipe behind the delicious Jelly Krabby, Patty made by Spongebob. But its beautiful slimy tentacles sting and can leave a souvenir on a lucky victim's skin. There are several popular methods to alleviate the jellyfish sting and one of them is peeing on the affected area. However, medical professionals discouraged this method because it will only trigger the stinging sensation more.
Jellyfish tentacles contain stinging cells, cnidocytes which discharge tiny harpoon-like stingers plus a venom when touched. Some venom can penetrate into the cells and cause detrimental effects biologically. Touching the affected area or pouring it with alcohol or pee can fire off cnidocytes. Urine act as a neutral solution that moves the tentacles around, therefore triggering more stinging cells. Another popular treatment that does not work is scraping the stung area with a credit card or shaving. Scraping the wound applies pressure that causes the stinger to release more venom. Rinsing with seawater can help to rinse them off but would not chemically prevent them from firing.
So the best first aid for the jellyfish sting is dousing it with acetic acid or vinegar. It deactivates the stinging cells by lowering the pH level then pluck off the tentacles with tweezers carefully. To ease the pain of the sting, apply a heating pad which can also inactivate the venom.
So refuse any help that tells you to urinate on the stung area because it is not only ineffective but also disgusting.