Last month, a shrimp fisherman caught a goblin shark off the Florida Keys. After a few snapshots, he released the shark back, and it just swam away. This accidental catch was only the second goblin shark on record in the Gulf of Mexico; the first was seen over 10 years ago.

First described in 1898, goblin sharks (Mitsukurina owstoni) have an unmistakably long, flattened snout at the end of their distinctly long head. A series of sensors, called ampullae of Lorenzin, can be found on the protuberance, and they're used for electrodetection of prey. ( Watch a video of its crazy jaw thrusting forward, catapulting its slender teeth to catch its prey.) They’re pinkish white with bluish fins. These bottom-dwelling sharks live in the deepest parts of the ocean, as far below as 4,265 feet (1,300 meters). And even though they’ve been seen near the surface in the Atlantic, Pacific, and Indian oceans, few specimens have ever been caught.

The shark was caught when Florida fisherman Carl Moore pulled up a net from more than 2,000 feet (about 600 meters) below. "First thing I told them boys was, 'Man, he's ugly! Looks prehistoric to me,'" Moore tells CNN . He's probably one of 10 people who have ever seen a goblin shark alive.

Just last week, his photos made their way to the U.S. National Oceanic and Atmospheric Administration (NOAA) Fisheries Service, where the information was eagerly devoured. “We don’t know how long they live; we don’t know how often they reproduce, or even how big they are when they reproduce,” NOAA’s John Carlson tells National Geographic . “They’re a mystery.”

By Moore’s account, the goblin shark was 18 feet (5.4 meters) long. “I didn’t get the tape measure out because that thing’s got some wicked teeth, they could do some damage,” Moore tells the Houston Chronicle . Judging from the photographs, Carlson and colleagues believe its length was more like 15 feet (4.5 meters) long. The researchers also believe the catch was female. Males have claspers -- two fin-like appendages near the tail -- that they use to hold on to females while mating.

NOAA Fisheries Service scientists are working with Moore to collect information about this rare sighting for a paper to come.

Image: Carl Moore via NOAA Fisheries