When you think of plankton, you might think of docile, intricately shaped microbes gently swaying in ocean currents while generously providing food for all manner of sea creatures. Serene. Charming. In reality, they’re little savages who constantly take each other out with sophisticated ballistic weapons.

In a new study published in Science Advances, researchers nabbed the first high-resolution images of those impressive arsenals. The militarized microbes are packing spears, harpoons, and miniaturized versions of a Gatling gun, complete with up to 15 barrels. The images and analysis provide the most detailed assessment yet of plankton’s elaborate weaponry. Those ballistics were hypothesized by some to be the evolutionary root of similar ballistics seen in other, distantly related sea creatures, such as jellyfish. But with the new data, the authors, led by researchers at the University of British Columbia, suggest that the microbes’ arms evolved separately and are uniquely complex.

To get the money shots, the researchers used focused ion beam scanning electron microscopy and assembled the images to create 3D reconstructions. They started with Polykrikos kofoidii, a single-celled eukaryote in a group called dinoflagellates. They’re known to use a harpoon-like weapon to hunt down other plankton critters, including ones that cause toxic algae blooms.

The researchers in Science Advances showed that the P. kofoidii use a one-two punch to stop, pierce, and then tow prey in. First, a needle-like structure called a taeniocyst launches and makes first contact with prey. What that contact accomplishes precisely is unclear, but the taeniocyst adheres to the prey, and researchers observed them violently releasing some amorphous content—a poison perhaps?

Next, the P. kofoidii fires a second shot. This one, a type of organelle called a nematocyst, is like a harpoon. With a stylet, the nematocyst pierces the prey, which then gets towed in.

Another dingoflagellate, a wild-caught Nematodinium, is topped with an intricate rosette-like structure that crowns a nematocyst with 11 to 15 barrels. These barrels ring the top of the Nematodinium’s structure, making it resemble a Gatling gun.

The researchers also did a genetic analysis to try to understand how these structures evolved and see if they made their way into distant relatives, cnidarians, some of whom use similar ballistic weapons. This group includes sea anemones, jellyfish, box jellies, and Hydrozoa, including the Portuguese man o' war. But, after sifting through the genetic blueprints of more than a hundred dinoflagellates, the researchers didn’t see any evidence that the weapons were shared or related to those used by cnidarians. Instead, the dinoflagellates seem to have developed their weapons independently.

Together, the authors conclude: “Despite the misconception that phytoplankton are passive cells, eukaryotic algae have given rise to (and arose from) multiple predatory lineages and, in the process, have independently evolved sophisticated ballistic organelles that exceed those of animals in complexity.”

In the video below, you can watch them in action:

Science Advances, 2017. DOI: 10.1126/sciadv.1602552 (About DOIs).