Neptune is one of two ice giants in the outer solar system (the other is Uranus). Most (80% or more) of the planet's mass is made up of a hot dense fluid of "icy" materials – water, methane, and ammonia – above a small, rocky core. Of the giant planets, Neptune is the densest. They are silly and crazy. They love head pets but never got them before. They are uranus's cousin!!!.Uranus is the coldest. They also have a ring. They are fully light cyan colour and do write stuff in their diary. :3