One of the most famous Reddit posts of all time was from a user who, convinced that he was losing his mind, asked the internet for help on missing bits of memory and notes he wrote to himself that made little to no sense. Another user correctly flagged his symptoms as carbon monoxide poisoning and literally saved his life.

What to Know About Carbon Monoxide Poisoning
Miller Gardner, the 14-year-old son of the retired Yankees player Brett Gardner, died from carbon monoxide poisoning while on vacation in Costa Rica. Here’s why the gas is so dangerous.
nytimes.com
