A Gulletbeast?
The Gulletbeast was an aquatic creature from the seas of the planet Lamaredd. It was similar to a whale in aspect, having a powerful tail and wide, webbed fins to attain a high swimming speed. Gulletbeasts could see in the dark. The biggest Gulletbeast ever seen by Humans was 750 meters to the tail and had a 200-meter mouth.
Gulletbeasts commonly swam while opening the mouth, which allowed them to eat anything in their path including any other fishes — as there were little creatures bigger than a Gulletbeast in their environment. Human-operated trawlers were known to be swallowed by Gulletbeasts — in one bite. In that case, unpanicked prepared crewmen could survive by shooting all the available weapons to a little nerve bundle in the roof of the mouth: If that part was damaged, the beast would spit anything in its mouth. The lucky captain would then depend on his skill, as the boat could still sink, full of water because of the ordeal.
Gulletbeasts were territorial creatures that disliked the presence of other Gulletbeasts in their territory. One month every four years, however, Gulletbeasts were in heat and southern waters became overcrowded with Gulletbeasts, fighting for the right to mate with a chosen pair.
When Lamaredd was settled by Hugo Bartyn and his people in around five hundred years before the Battle of Naboo, Gulletbeasts were discovered. Bartyn's Landing was a fishing community and Gulletbeasts were one of the greatest threats, and the most feared predator, to the fishermen. Fishermen soon learned their mating customs so that they could make the most of that moment. They also geared their ship with energy weapons to fight Gulletbeasts, even in a planet where energy weapons rarely could find a replacement clip — because powder would rarely survive a fishing trip.
Due to the problem they represented, Hugo Bartyn, a great professional hunter, tried to exterminate the creatures, but he failed. Five centuries after his times, Gulletbeasts still roamed through Lamaredd and sometimes attacked even ferry boats.
In 29 BBY, the native sentient species known as Menahuun began attacking fishing trawlers. As the boats disappeared on the open sea, the locals mistakenly believed that the Gulletbeast population had increased.