I dunno whether to mark this NSFW or not but do your worst.
Without hesitation, the smell of persons who didn’t took a shower for a long time, the only smell so far able to make me puke.
Rotten salmon in my fridge after making Sushi 4 days before. I’ve never went from hot to cold to hot just from smelling before.
A friend of mine had to move to a much smaller apartment for a year (remember this) for financial reasons. He put a lot of stuff in a storage facility and one of it was a fridge-freezer-combo. When we finally took everything out we noticed a stenching smell. We opened the freezer and it was full of rotting meat…
A fridge unplugged for 3 weeks with food inside that I had to clean out. I haven’t smelled a rotting corpse but I imagine that it can’t be far off.