A very useful early ocean going mount. Be sure to set it to passive so it doesn't swim off to where you can never find it again. Also level up on your oxygen so you won't have to make it surface so you can breathe all the time. Quite possibly a good ocean beasty tamer. Mine swam off killing things and I never saw it again. Emphasis on setting it to passive.
The #1 thing that needs to be in TLC 3. At least make it as large and powerful as the mosa. Should have one of the highest attack dammages because scientists have proven that the megalodon has the most powerful bite of any living thing and is strong enough to crush a tractor trailer.