Here's a fish story that's almost as bad as tales of the legendary candirú. The climbing perch (Anabas testudineus) is a small fish that possesses an organ that allows it to breathe atmospheric oxygen for several hours at a time. Its musculature also allows the fish to move terrestrially. (Watch a tidbit of the above video. See those perch flopping about on dry land? Get that image firmly in your mind, and apologies in advance.)
These handy evolutionary traits recently resulted in a nightmarish scenario when 12-year-old Philip Muan of Rumah Endawie Nangka Jela Engkari, Malaysia got one of these hardy creatures stuck in his throat for 14 hours. As Star Online explains:
He removed the hook and tried to bite the head of the [four-centimeter-long] fish to kill it but it slipped into his mouth and lodged itself in his throat [...]
It was already 11 PM by the time he arrived [at the hospital] and the boy was spitting blood. The fish had by then died and a foul smell emanated from the boy's mouth. The operation to remove the dead fish took just a few minutes.
This incident happened at 9 AM in the morning, so this poor kid spent most of his waking day with a confused fish slowly dying in his throat. If "wiggling fish that can breathe air asphyxiates in your gullet" isn't a form of obscure underworld torture on display at Singapore's Haw Par Villa amusement park, it really deserves to be.