The Serpent is a class of war junk in the service of the East India Trading Company. This vessel carries 11 deck cannons and 17 broadside cannons on each side.
Appearing around level 44, with approximately 19,000 Hull Points.
In addition to traditional ammunition, they fire with firebrands and explosives. They are often found on the edges of the seas, or helping a treasure fleet. There are only a few present at a time, but they may appear randomly.
Read more on war junks here.