Seama resembles an octopus, with a main tentacle making for its body and smaller ones that make for the arms. It has sharp teeth.
At one point while exploring the Galleon Minerva, Vepar can be seen breaking a hole on the ship's hull and spewing three energy balls inside which then transform into three Seamas, hinting these creatures to be her progeny.
Seama is very similar in appearance to the Wo-Class enemy from the Kantai Collection series. This may be deliberate as Wo-Class is the spirit of a sunken ship and Seama appears in sunken ships in both the demo and Curse of the Moon.