According to the Loopers' Nest discovery:
"Loopers are mysterious creatures, rarely seen by even the most seasoned of sailors. They nest in stone reefs, and their young stay in the nests until they mature. Loopers are white at birth, but turn various colors as they age."
They are famous for their high hit and dodge rates and tendency to run away from battle after they've hit the player or at the beginning of battle. The actual discovery that can be seen when sailing is a fairly large in size baby white looper staying in its nest.
Vyse and company can also fight a giant orange looper and Elcian, a black looper. Both fights are optional. Defeating the giant looper yields a lot of normal experience. Defeating Elcian yields a lot of gold, normal experience, and magical experience.
The giant orange looper can be found floating around near the Loopers' Nest Discovery. Because it is so huge, Vyse will not fight it on the deck of his ship, and will instead fight it as though it were a gigas or giant monster. Like every other looper in the game, this giant creature has a high dodge rate, and it will run away from battle. However, it only runs from battle when it takes too much damage. It only has one attack, Looper Ring, which hits the ship harder than most gigas. Luckily, if the player fails to defeat it the first time, they can try again until they do. After the giant looper is defeated, it will not re spawn.
Elcian, the black looper, can be found in the Dark Rift where the player fought the giant worm thing the first time they pass through the Dark Rift to get to Yafutoma. Elcian will only appear after Galcian is defeated. Elcian will still dodge a lot, but his dodge rate is a hundred percent lower than most other loopers. However, unlike other loopers, Elcian will not die in one hit. This looper does give a lot of experience, both normal and magical, though, and it re spawns.