The octopus, which has been given the nickname "Casper" for its friendly ghostlike appearance, was discovered in February of 2016 off the Hawaiian archipelago and is unique for a few reasons. Scientists observed it swimming slowly at about 2.6 miles (4.3 kilometers) deep, much lower than any other octopod (a group of invertebrates that includes octopuses) without fins has ever been seen. Other unique features of the octopus: it completely lacks pigment, giving it a very ghost-like appearance, hence the name. And because there's little food in the deep sea, and it takes a lot of energy to build muscles, the ghost octopus has a gelatinous consistency.
"I knew it didn't look like anything that's been documented in the scientific literature." That's what Michael Vecchione, a National Oceanic and Atmospheric Administration zoologist working for the Smithsonian Institution, told National Geographic after he got his first glimpse of an unusual looking octopus on an NOAA ship's live feed. The animal turned out to be part of what is likely an entirely new species, and was nicknamed the "ghost octopus."