Mersidon is a marine Pokémon that resembles that of a masculine mermaid. Most of its body is mixed in colors with a long dark blue tail with a trident like end. Its head resembles a lightning strike with a white and yellow beard.
Mermarine is the female counterpart of Mersidon. Mersidon can only be male.
Mersidon's tridents on their tails act as a lightning rod, directing thunderbolts from the sky to either strike down their foes or power their own attacks.
As the name implies, Mersidon is based off a cross between a Mermaid/Merman and the Greek Mythical God of Sea, Poseidon. It's Electric Typing also could apply it also takes inspiration with Zeus, another Greek Mythical God, which Zeus is the God of Thunder.