Mosasaur is only really good for 2 things; #1 being it allows you to easily kill any creature under the depths of the ocean, therefore getting Silica Pearls is easy and fast since nothing can really harm you. #2 Mosasaurus is perfect for get Deep Sea loot crates, because if anything is by the Crate your Mosa ( if high enough level ) should be able to kill whatever it is "guarding" the drop!

More Mosasaurus Taming & KO Tips