X-Mosasaurus

Warship

Mosasaurus has high health and damage, which makes it useful in battle. The platform saddle also allows for cannons and siege weapons, allowing for naval warfare.

Level up: Health and Damage

Aquatic Tank

Having a base health equal to the Alpha Raptor, the Mosasaurus can take massive damage (Level Health and Melee Damage).

Oil Rig

Due to the fact the Mosasaurus can carry a large amount of weight, you can make it built for collecting enormous amounts of oil and converting it to gasoline. While not an ideal or recommended use, you could also use it for collecting crystal as well.

Level up: Weight, Damage and Health

Bio Toxin Gatherer

Unlike most aquatic creatures, tamed Mosasaurs do not attract Cnidaria. Additionally, due to how group aggro mechanics work, other Cnidaria won't turn against your Mosasaurus if they are killed in a single attack. This makes the Mosasaurus an ideal creature for safely wiping out swarms of jellies and for gathering their Bio Toxin, as long as the damage dealt is high enough to kill them in one hit.

Level up: Melee Damage

Transport

The platform saddle provides adequate room for transporting goods, medium- to small sized dinosaurs, and players.

Travel

A Mosasaurus's high base speed combined with its weight stats makes it ideal for travelling. You can also add a platform saddle to protect and transport other players. Mosasaurus also has better stamina consumption compared to other aquatic dinos with the same health and power.

Damage

The mosa has extremely high damage, though it is let down by its poor mobility (turning radius and lack of ability to swim backwards makes landing consistent bites somewhat tricky) and practicality with regard to electrophorus and Cnidaria, making the Tuso a better choice in most if not all situations.