Same!
There's a story I remember reading about - a dude on holiday went swimming in the Amazon river and accidently ingested a bit of water. He got checked out but there wasn't anything wrong with him.
Went back to Europe / wherever and he began drastically losing weight. No matter how much he would eat - and he was eating big meals and always going hungry. He eventually got checked out again and the doctors found a massive worm / snake type thing situated in his stomach - literally anything he would eat would go to this thing and grow that instead.
He eventually had it removed but it made me so freaked out about swimming anywhere with my mouth open!
Anyway - whilst writing this post I tried googling this story and found this instead
Inside The Legend Of The Candiru, The Amazon Fish That Allegedly Targets Men’s Penises
The candiru is a tiny parasitic fish that lives in South America — and supposedly has a penchant for swimming into the human penis.
Of all of the beasts that prowl the Amazon region, few are creepier than the candiru. A parasitic freshwater catfish that’s feared even more than the dreaded piranha, the tiny candiru reportedly waits for its unsuspecting prey to step into the river before striking in the most painful way imaginable.
It’s also only about an inch and a half long — but don’t mistake its small size for weakness. In fact, terrifying stories from the region allege that the candiru has a habit of swimming right up inside unsuspecting swimmers and fishermen’s urethras — then refusing to leave.
Candiru: The Amazonian Fish That Can Swim Up Your Urethra (allthatsinteresting.com)