Garn

"Okay, you bloody idiot, you let one of those on my fookin' boat? You havin' a laugh? I ain't cleaning that up!"

— A mad sailor

Probably bigger than you think

Commonly found attaching themselves to the underside of boats and ships, garn are notoriously difficult to get rid of. While similar in anatomy to a pill bug, garn are significantly larger and are much, much tougher due to the half inch thick chitinous plate across their spines.
Their sharp claws are capable of digging into hardwood, where they slowly eat at the hull of ships, not unlike termites. For small boats, this poses a significant threat, especially to rowboats, however they are much more easily spotted on small ships, as their impact is usually felt. On larger ships, their impact is felt a lot less throughout the ship, making it much harder to know when they may have attached themselves.
While you may be able to deter garn from attaching themselves to your ship by covering it with thick layers of paint, it is a time consuming process and has to be refreshed every couple of months.

No, still bigger than you think

Garn do have a breeding cycle, though due to their main living environment being the deep sea, it isn't particularly well researched. What has been researched about it, however, is that it takes place roughly every other year and involves digging into the sand and laying dozens of eggs.
Unsurprisingly, garn mostly die due to being removed from their food, as this process snaps their legs off. Without legs, garn have no method of propulsion through the water, and as such usually find themselves either eaten by another creature or they die of starvation at the ocean floor.
Despite being a nuisance to ships because of their diet, garn are entirely harmless and just look rather frightening. Most people believe that their most frightening feature is the mass of teeth they have which appear to always be chewing, even if there is nothing to chew on, though others think it's simply their entire being.

Lifespan

8 to 10 years

Average Weight

2 to 2.5lbs

Average Length

Approx. 15 to 20 inches