So, I’m old enough to remember that episode of Friends where Monica got stung by a jellyfish and Chandler had to pee on her, but this idea has been around long before that. People have been peeing on jellyfish stings and it will make things worse. Jellyfish have stinging cells called pneumaticists that actually inject venom into you and the myth says that urine will stop those cells from firing, but it could actually do the opposite, making more pneumaticists go off and making the sting worse.
Where did this come from? I don’t know, somebody wanted to pee on somebody I guess.
So, actual advice - Venom experts say that vinegar is much better at stopping stinging cells than pee. They also say that you should pluck the tentacles off with tweezers if you can, because that will disturb the unfired cells less than scrubbing with seawater or a credit card. Finally, heat might break down some of the compounds and help the pain go away faster.
So, can we put this one to bed now please?