Animal Feces
Nothing really illegal here, just inconsiderate to your fellow passengers who are trapped with you on a plane with poor ventilation. This person thought they could easily take on a large bag of animal feces to study back home, but to their surprise, they were rejected.
Apparently, it’s some type of restriction on these things, not to mention the terrible smell it would create and a potential health hazard. We aren’t sure if this would be allowed in luggage, but for a carry-on item, it was a no-go. Make sure you talk to the airport authorities ahead of time if you want to bring animal feces with you.