For example, Trove has added a new underwater dragon called Thallasion, Shaper of the Currents. If you manage to hunt down this “very rare spawn” in his watery lair and somehow kill him, you’ll be able to accumulate fragments that can create… Thallasion, Shaper of the Currents. Only now as a meek mount and not a surly boss.
Thallasion is reportedly pretty tough to take down, as he’s constantly regenerating health through the water and also by leeching hit points from invading players. For your troubles, the mount version offers some nice stat bonuses and the sight of your ride spitting out a stream of bubbles.