Try to give a concept, base stats(remember 600!), and possible moves it can learn. Here's mines:

Based on a Styxosaurus, it would become gradually more aquatic and dependent on water as it evolved. It has a giant blowhole on its back.

Dragon/Water Type

HP: 130
Atk: 95
Def: 100
Sp. Atk: 105
Sp. Def: 95
Spd. 75

Regular Abilities are Dry Skin and Damp. Hidden ability is Drizzle.

Moves:
Recover
Water spout
Muddy Water
Crunch
Aqua Jet
Sludge Bomb

I hope it's not too good.