What survival myth is completely wrong and can get you killed?

https://lemdro.id/post/37509347

Drinking your own pee will end up dehydrating you faster, contrary to how confident Bear Grylls is in it being a decent strategy.
But if youโ€™re lost in a desert you should rub pee on your skin to conserve water. (Iโ€™m not kidding thatโ€™s a real thing.)