Sharkyn

The Rainy biome is where Sharkyn becomes realistic. Its base chance is 1 in 10,000,000, but inside rain the wiki gives it 1 in 2,500,000, a fourfold boost before any potion. At 1x luck that is about 2.5 million rolls while it rains; at 10x luck, roughly 250,000. It is an Exalted tier aura from Eon 1-14 and, according to the wiki, remains obtainable.

The theme is the deep ocean, mostly light blue and white. A shark figure with fins on the head and arms and a swivelling tail on the back stands in the middle, while many fish circle counterclockwise at high speed and bubbles drift upward. Three rocks form a triangle and send ripples across the water. Its in-game text describes a poor servant of a ruthless tyrant, forced to show only love and praise. The aura has no active ability, but its mutation Sharkyn : HammerHead does. Credits go to TYINULTY, literally_starfall and Letaw_66l.