A hawksbill sea turtle was recently found that is stumping scientists.
The turtle was glowing, but not through bioluminescence like a firefly or plankton that turns tides blue.
It's biofluorescent, according to marine biologist David Gruber.
The way it works is, rather than producing its own light, the turtle's shell reflects blue light as red and green.
Researchers have recently discovered biofluorescence in some fish and crustaceans but never a reptile like the hawksbill.
While biofluorsecence is used in some animals to attract prey, hawksbills largely feed on sponges and algae, so a more likely hypothesis — as another marine biologist told National Geographic — is camouflage.
Still, it'll take more research to understand — something that might not be possible with the hawksbill, which is critically endangered.
See more of the stunning species:
Hawksbill sea turtles
This turtle is fluorescent, and scientists aren't sure why
This April 21, 2010 photo shows a hawksbill sea turtle as it cruises over a reef just off the shore of Curacao. From mesmerizingly decorative buildings to lush coral reefs beneath sparkling turquoise waters, this Dutch Caribbean island has more than enough sights on land and under the sea to keep visitors restfully busy for a week. (AP Photo/Brian Witte)
A preserved hawksbill sea turtle is displayed at a news conference at JFK international Airport, Monday, June 16, 2014 in New York to highlight efforts by U.S. Customs and Border Protection and U.S. Fish and Wildlife to deter illegal trafficking in wildlife. The animals displayed at the news conference were seized from baggage and cargo arriving at the airport. The government is cracking down on the illegal trafficking, saying some of its import-export activity may be linked to terrorists. (AP Photo/Mark Lennihan)
A Hawksbill sea turtle is seen swimming on January 15, 2012 in Lady Elliot Island, Australia. Lady Elliot Island is one of the three island resorts in the Great Barrier Reef Marine Park (GBRMPA) with the highest designated classification of Marine National Park Zone by GBRMPA. The island of approximately 40 hectares lies 46 nautical miles north-east of the Queensland town of Bundaberg and is the southern-most coral cay of the Great Barrier Reef. (Photo by Mark Kolbe/Getty Images)
Hawksbill Turtle, Eretmochelys imbricata, Namena Marine Reserve, Fiji (Photo by Reinhard Dirscherl/ullstein bild via Getty Images)
In this photograph taken on April 20, 2010, four month old Hawksbill turtles swim into the sea after a symbolic release by conservationists at the Thousand Islands National Marine Park in Pramuka island north of Jakarta. Hawksbill turtles, known by their scientific name Eretmochelys Imbricata, are listed as an endangered species by the International Union for the Conservation of Nature and Natural Resources. Hunted for their flesh, shell and eggs, plus destructive fishing methods have threatened the survival of the sea turtle. Indonesia's conservation efforts include aiming to stop the illegal trade of Hawksbill turtle products and protect its natural nesting grounds. AFP PHOTO / ROMEO GACAD (Photo credit should read ROMEO GACAD/AFP/Getty Images)
A Hawksbill sea turtle is shown in this underwater photograph taken while scuba diving off the Caribbean Island of Bonaire May 17, 2009. (AP Photo/David J. Phillip)
Day-old hawksbill turtle hatchlings swim in the pond prior to being released into the sea off Morong, Bataan province about 110 kilometers (70 miles) west of Manila, Philippines Saturday Nov. 18, 2006. More than 40,000 turtles were released into the sea by a community-based Turtle Conservation group PRRM (Philippine Rural Reconstruction Movement) since 1999 and environmentalists predict between 1 and 3 percent survived. Close to a hundred day-old hawksbill hatchlings were released Saturday. (AP Photo/Bullit Marquez)
Hawksbill Turtle - Eretmochelys imbricata floats under water. Maldives Indian Ocean coral reef. (Photo via Getty Images)
Hawksbill Turtle and Diver -- Maldives. (Photo by Ian Cartwright via Getty Images)
(Photo by Stuart Westmorland via Getty Images)
Hawksbill sea turtle (Eretmochelys imbricata) swimming over coral in Jackson Reef, Tiran strait, Red Sea. (Photo by Joao Pedro Silva via Gety Images)
Hawksbill turtles have a narrow snouted hawk-like head. They are critically endangered. (Photo by Manoj Shah via Getty Images)