Fish Out of Water

Fish in the Ocean with a Truffle Worm (a rare glowing mushroom-biome critter, caught with a bug net) as bait and Duke Fishron erupts out of the water furious. He's the hardmode skill check: sharknado charges, bubble walls, and a lights-out enrage in the final phase. A very long runway or big loop, high-tier wings, and don't stray from the ocean or he enrages harder. His drops (Tsunami, Razorblade Typhoon, Fishron Wings) outclass most of the tier - worth learning the dance.