2getting one
Only worlds rolled as For the Worthy or Zenith contain it, so on an ordinary map there is no route to one short of trading with someone who plays those seeds. Inside them it rides along as a bonus roll on Dungeon chest loot, which means every locked gold chest and every biome chest gives you a shot at it on top of whatever weapon or accessory it was already holding.
Once the Dungeon has been picked clean, fishing takes over. Golden Lock Boxes hooked out of the water down there roll from the same table and never run out, so a slow evening on a line will get there eventually where chests cannot.
Nothing about it changes your character. It fills the body vanity slot and exists for the costume.