The aquatic scarab gem is the rarest item in the mod as its recipe requires both a scarab gem and a piece of Dominican Amber, two exceedingly rare Items. Its only purpose is for taming aquatic and semi-aquatic prehistoric creatures. These creatures are sarcosuchus in the 7.2 update and mosasaurus, liopleurodon, and spinosaurus in the 7.3 update. As of the 8.0 update, liopleurodon no longer requires it, instead being tamed via traditional methods. To tame them, the player must fight the adult animal (age of adulthood can be found on the creatures' pages) until it enters a "weak" posture, which looks a lot like a sleeping posture. The weakened creature then must be right-clicked with the gem, which results in the loss of the gem and the complete healing of the now-tamed creature.