What are you convinced is the worst smell in the world?

The smell of a dead animal. We came across a rotting giraffe carcass on a safari walk once. I have never in my life smelled something so horrible.
— anjadup

Sweaty hockey pads in the back of a Volvo 740 after a day in the sun. I have experience.
— empw

Cheddar cheese popcorn when you don't know you're smelling cheddar cheese popcorn. *Sniff sniff* Oh my god, who fucking died? Did they drown in used gym socks? *sees somebody just microwaved cheddar cheese popcorn* Ooh! Can I have some?
— captainfatastic

Rotting human Nothing quite like it, nothing that will ever erase that memory
— Facerless

That smell of tooth decay, generally in older people. It's the smell that sticks to your clothes, your skin, your hair. It's a smell that can make you lose your appetite immediately.
— DetroitEXP

Our old pitbull spent the day on the farm eating cow shit, then vomited all of it up in a pile on the floor grate that was emitting heat. That smell was hellish, as if demons were festering inside the puke. I have never smelled anything worse.
— gnrlysrs

[Thioacetone](https://en.wikipedia.org/wiki/Thioacetone) > Thioacetone has an intensely foul odor. Like many low molecular weight organosulfur compounds, the smell is potent and can be detected even when highly diluted.In 1889, an attempt to distill the chemical in the German city of Freiburg was followed by cases of vomiting, nausea and unconsciousness in an area with a radius of 0.75 kilometres (0.47 mi) around the laboratory due to the smell. British chemists at the Whitehall Soap Works in Leeds noted in an 1890 report that dilution seemed to make the smell worse and described the smell as "fearful". Thioacetone is considered a dangerous chemical due to its extremely foul odor and ability to render people unconscious, induce vomiting, and be detected over long distances.
— 0xD153A53

When dogs get this smell, from the glands in their rectum. This juice leaks out... I don't know what it is called. We just call it 'butt smell.' If it gets on your pants, good luck. Took in my parents dog to the vet, they took care of it and the entire room smelled like it. I gag thinking about it.
— Economy_Cactus

Top 10 Answers