A shark surprised a team of researchers exploring the Solomon Islands – by turning up fairly unexpected place.

Sleeper sharks, though rarely observed, are native to the Pacific and Atlantic Oceans, as well as Antarctica and Tasmania. But this Pacific sleeper shark startled researchers, showing up just east of Papua New Guinea inside an active volcano.

"We were freaking out," said University of Rhode Island Ph.D student Brennan Phillips to National Geographic.

Observing volcanic activity earlier this year, Phillips and his colleagues were dropping video camera packages into the deep sea near to the Solomon Islands. After retrieving the footage of one such “drop”, they noticed something strange and blob-like on one of the video’s thumbnails.

The odd, “large brown blob” was later identified through its coloration and physical characteristics as a Pacific sleeper shark, which makes the volcanologists’ sighting the southernmost ever of the species ever documented.

The Pacific sleeper shark can grow up to seven meters long (23 feet). The largest confirmed Pacific sleeper shark measured 4.4 meters long (14 feet) and weighed 888 kilograms (1,958 pounds). They can swim noiselessly and with very little body movement, making their prey very easy catches.

Check out the video below from National Geographic of this rare sighting.

[H/T: National Geographic]