Cordyceps. Because Mother Nature likes to be a creepy bitch sometimes.
I recently bought and played “The Last of us Remastered” and it got my creative gears turning. Changelings are depicted as insect like, so it sort of made sense that Cordyceps would be capable of infecting them. I might right a fanfiction about this idea in the future. Possibly.
Wait, does that mean you don’t like things such as South Park and Team America World Police, since they have dirty/raunchy shock humor? Though even if you don’t like them, I still do respect your opinion.