Good fighter, immune to jellies, supernatural healing boost at the surface, produces oil in its inventory, impervious to squid grabs, looks kinda cute too, only one bad thing about it: it gets squashed in the deep! Only slowly but the damage is there!

Even if you don’t have the saddle Engram for it you can use it as a way to get free oil 😱😱😱😱. Like so low level ppl can see

Oh my god it does not get effected my jellyfish this is one of the best creatures ever.

Mine just ate an alpha mosasaur.

Good for farming bio toxin, as it can attack Cnidaria without being stunned or knocking off the rider. Takes damage when it goes too deep, though surfacing rapidly heals it.

Up if it would be cool to have a mini platform

Basilos, one of, if not, the best aquatic mount in the game. Not able to be stung by the jellyfish, healing quickly at the surface, and for being a whale for ARK's sake. They have tons of weight, damage, and, best of all, the potential for a MASSIVE health pool. I bred a fully imprinted, non-mutated Basilo for the first time today, and after killing an alpha Meg and Leedsichthys, it has nearly 200,000 health. Damage-wise, it isn't too crazy, but it is especially good for an aquatic mount. The only aquatic creatures to rival the Basilo in its capabilities are the Most and Tuso, and possibly the Plesio as well. The Miss was the original King of the Sea, but ever since Jellyfish were added, they have been in a fire need for a TLC. The Plesio is fast, but it doesn't do as much damage and is not as manuverable as the Basilo. That leaves the Tuso. It has a long reach, but Basilos are not affected by its grip. This truly proves they are the King of the Ocean.

This thing is insane mine took out 5 megaladons at one time

Steelslaughter here,
Perhaps the most versatile, combat oriented, tankiest, and easiest water tames, I’ve converted two basilo’s into near-invincible war machines I can only describe as ARK’s equivalents of an underwater John-117. I, no joke, led 20 or so megalodons to one and all of them were shredded in under a minute. Also they produce oil, which is nice, but it spoils, so I usually solve the oil situation with my dunkleosteus. Very well rounded and a PASSIVE tame, would certainly recommend!
Peace out,
Steelslaughter