The deep ocean keeps producing creatures that look like they were designed by someone who’d never seen an animal before, and scientists just added 31 more to the list.

An international research team aboard the Schmidt Ocean Institute’s Falkor (too) vessel spent time surveying the tropical midwaters of the South Atlantic, off the coast of Brazil, and came back with a pretty strange haul. The midwater zone sits between the sunlit surface and the deep ocean floor, and according to Science Alert, it’s the largest habitat on Earth—one that remains poorly understood despite covering most of the planet.

“The largest habitat on Earth, the midwater, is filled with incredible animals we are only just starting to understand,” said Karen Osborn, a research zoologist at the Smithsonian National Museum of Natural History and the expedition’s chief scientist.

Scientists Found 31 New Species in a Part of the Ocean We Barely Understand

The new species include ghostly gossamer worms, comb jellies with glittering finger-like appendages, and larvaceans that construct balloon-like mucus houses to catch drifting food particles. There are also siphonophores, which are colonial creatures made up of specialized clones that function as a single organism. And giant rhizarians, which are single cells large enough to see with the naked eye, because the normal rules don’t apply down there.

What made this expedition notable, beyond the sheer number of discoveries, was how the scientists found them. Deep-sea animals are soft and gelatinous by necessity—their bodies are built to handle extreme pressure, which also means they’re easily destroyed by traditional collection methods. The team used three non-invasive imaging systems attached to their remotely operated vehicle, SuBastian, including laser-scanning tools developed by the Monterey Bay Aquarium Research Institute and a shadowgraph camera from Japan’s marine science agency.

They also deployed a Stanford-developed microscope to image the living cellular structure of a single-celled microbe in 3D at sea, a first of its kind. A hydrodynamic treadmill, essentially a circular chamber that simulates an endless water column, allows researchers to observe microbial behavior without disturbing them.

“It’s an incredible honor to not only view and experience this rare and inspiring midwater life, but also to be able to work towards describing and sharing that life broadly through the use of novel, non-invasive technologies,” said Kakani Katija, a bioengineer at MBARI.

The goal, going forward, is a future where marine scientists can study ocean life in its natural environment without having to remove it. Given what’s living down there, that seems like a reasonable compromise for everyone involved.