Stationary cameras recorded as many as 10 gloomy octopuses sharing a high-density site in Jervis Bay, Australia, for more than 20 hours across 2015 and 2016. The animals pulled silt, shells, or algae into their arms, held the material beneath the web joining those arms, and aimed their siphon through it. A forceful jet then propelled the debris several body lengths.

Many throws cleared food remains or excavated dens. Some crossed another octopus’s space, and a minority hit. Females threw more often than males. In one sequence, a female repeatedly launched silt toward a male that had attempted to mate, while he ducked. Potential targets sometimes raised an arm before the material left, as though anticipating the trajectory. Dark, uniform body patterns were associated with more vigorous throws and more hits.

Those patterns make a socially directed throw plausible, not a proof of spite. Most launches struck no octopus, the team saw no recipient “return fire,” and clearing a den can send debris through a crowded neighborhood without a personal goal. The verb still fits the mechanics: material is gathered, positioned, and propelled away. What remains uncertain is how often another animal is the intended destination rather than the inconvenient object downrange.