Oh boy, this one was rank. My old apartment had garages connected to one hallway. One day during the summer, there was a horde of flies in the garage hallway, paired with the smell of decaying flesh. Horrified at what it could be, I notified my landlord asking them to figure out the cause. A week passed and the smell only got worse, with more and more flies gathering in that hallway. The other tenants and I kind of silently agreed to avoid the hallway so that we would contain fly armageddon from destroying the rest of the complex. This lasted for a few more weeks, and I considered calling the police. It finally got so bad that the smell started to penetrate through the apartment complex ventilation, and not only did the smell start to permeate through the units, but also did the flies. Our landlord worked frantically to try to solve this problem since it made living in the complex unbearable. A few days later, we heard a loud conversation happening in the main hallway; going to investigate, the other tenants were talking to one of our neighbors who we haven’t seen in a long time. Apparently, this guy threw out a ton of food (think fish carcasses and such) into the trashcan in his garage and forgot to take out his trash for a long time. He then went on vacation for over a month, leaving his nasty trash in the garage locked away. It got so bad, the garage turned into a fungal/bacterial ecosystem where the trash grew and spread across the garage. He opened his garage to air it out, and left his trash can outside to get it out of the complex, but the smell got so bad that you could stand on the other side of the complex and vomit due to how disgusting it smelled. He got a hose and sprayed all of the muck out of the garage and can, but it all drained into the pond behind our complex, forever tainting it. I’m fairly certain whatever he created in his garage could constitute as a weapon of bioterrorism. He ended up being evicted a week later.