Corrosive

Corrosive pays you back for hunting it in the right place. In the Corruption biome its chance is 1 in 2,400, compared with 1 in 12,000 anywhere else, a five-fold improvement. At 10x luck that is roughly 240 rolls in Corruption and 1,200 outside. It is a Unique aura added in the Era 7 update by ep1k_sol, and the wiki also lists a crafting route, though the details are cut short on the page.

On screen, a portal-like circle swirls beneath the player with a violet center that glows hard, while a purple haze wraps the body and tiny light-purple particles puff out of the portal, much like Nautilus recolored. It has no idle or walking animation, as many auras do. One interesting detail is in the cutscene: the normal roll shows a purple star expanding with a drop-beat sound, but a native roll in Corruption skips the star and goes straight from a black screen to purple edges that reveal the aura. The in-game text says it is slowly corrupting everything.