The study and the species are both real. The study and the species are both real. Researchers did observe and document Octopus tetricus throwing shells, silt, and algae at Jervis Bay in Australia, and it was published in PLOS ONE in 2022, so the core of the claim holds up. But the way it spread online is a pretty good example of how a nuanced study gets flattened into a much simpler story. The lead researcher Peter Godfrey-Smith actually said that most of the throws look more like den cleanup than targeted attacks. In one of the key observations a female threw material 17 times, and out of those 17 throws, eight hit another female and only one hit a male. That is not exactly the rock-throwing feminist icon narrative that went viral. The scientists themselves were pretty careful about it too, saying it is really hard to infer the motivation of animals and that not every throw that hit a neighbor was necessarily aimed at one. Some of it could have been accidental. The behavior is real and it is genuinely interesting, but the specific version where females are defending themselves from harassing males is mostly the internet doing what it always does, which is taking the most dramatic possible reading of a complicated study and running with it. The claim is partly true. The framing around it is where things get stretched.