Off the coast of American Samoa, an active underwater volcano towers above the seafloor, its upper crater the site of a four-year eruption.
Following the formation of a 1,000-foot lava cone between 2001 and 2005, the Vailulu'u site was investigated by the National Oceanic and Atmospheric Administration's underwater robot Pisces V.
The volcano spent the next two decades unexplored in the depths of the Pacific Ocean -- until now.
Ocean Exploration Trust, a non-profit research organization and NOAA partner, launched two dives with its Nautilus Exploration Program to search the Vailulu'u seamount at the beginning of October. It posted a video Oct. 2 on YouTube of the first dive.
"This seamount provides the unique opportunity to study a volcano in its early life, estimated to have been erupting only over the last 300,000 years," the organization said. "Check out the winding lava formations like the volcano pillar left behind as fresh lava erupted into cooling fractures in the slope!"
But it wasn't just geological formations that excited researchers as the underwater robot was launched from the Nautilus ship and reached new depths.
Two dives, one at a depth of about 2,000 feet and another at a depth of about 5,000 feet, revealed the unique and odd creatures that call the volcano home.
"While we're here, can we zoom on that little sea cucumber?" one researcher asked in the video.
"Oh my gosh, you can see whatever those organs are in there, those pink ones, like little hot dogs," another responded as the camera focused on a squishy, translucent animal with a slight purple color.
As the robot continued around the mount, researchers spotted a species of coral sticking out from the rocks.
It was bright red in color, a stark contrast to the gray piles of rocks protruding from the mount. Wrapped around the branches of the coral were what researchers called "associates," or species that live on and among coral colonies.
"This is a pretty spectacular location," one researcher said.
The associate species, not identified by the research team, have a central body and long extremities that wrap around the branches of the coral, according to the video.
What appeared most exciting to the scientists as they moved around the environment were multiple fish species.
One small pink fish was identified as a Chaunacops species, often called coffinfish or sea toads, according to NOAA.
"Oh I love them so much, so cute," one researcher said as the camera zoomed in on the incredibly round fish with two bulging eyes.
"This gives me cuteness aggression," another added.
Then, an "impressively-patterned juvenile batfish" was spotted straddling two rocks on the slope of the volcano "like a mountain goat," according to the video. Its body was swollen as if filled with air.
"They have massive inflatable gill chambers that expand ... the animal's body with sea water so they can hold their breath," one researcher said.
The fish used its strong fins to position itself as if it was "rock-climbing" up the slope, the organization said.
"He really does look like he's scaling the wall," another researcher said.
Most seamounts are remains of extinct volcanoes that haven't been active for an extended amount of time, NOAA said. They are shaped like mountains on the surface but typically have craters, linear ridges and "large, flat summits."
"Studies conducted over seamounts indicate that seamounts function as 'oases of life,' with higher species diversity and biomass found on the seamount and in the water around it than on the flat seafloor," NOAA says.
The Vailulu'u seamount is in the National Marine Sanctuary of American Samoa, a 13,581-square-mile region of protected ocean off the coast of the American Samoa archipelago, an U.S. territory.