Whoa, what an eerie little guy!! Cetopsis coecutiens apparently.
How did I never know about these? Apparently, yes, “Cetopsis candiru” is similar looking to a huge candiru and is known to tunnel into dead or dying animals so aggressively that it’s been proven to do so to humans, “hundreds of specimens” found in drowned corpses.
It’s believed some people may not have been dead yet; just injured or really, really drunk.
I need these in my life and apparently they aren’t all that difficult to get in the aquarium hobby.
This also answers an old mystery for me; I had a book of “weird nature trivia” as a kid, which of course didn’t source anything or offer latin names or anything, and one of the factoids was that a “whale-shaped catfish” was more feared in the Amazon than piranha for its habit of “biting big scoops” out of swimmers.
This actually seems to be convergent evolution with the cookie-cutter shark, same lifestyle! Teeth adapted to carve a piece from even very large animals and escape with it before they’re even noticed.