Lake sharks, some sharks swim upstream to give birth and than get stuck or lost, they can survive in freshwater for quite a while. Not to mention someone could just put a shark in the lake, which is ironically the plot of the movie “shark lake”
The tiny people in the telephone will decide to take up residence within my ear.
That I’ll be distracted as I walk up to the urinal, unzip, then realize someone’s already using it.
I used to drink until I would black out as a teenager/college student and I started to worry that I might do something super illegal or horrible and not remember it. Like I’d wake up with blood all over me and realize it wasn’t mine and then have no idea what I’d done, the cops would show up at my door, and so on. Needless to say I don’t drink that much anymore and it’s actually largely due to that fear.
Dogs. I never got bitten by a dog, but my heart beats faster whenever I see one.