The Two Deep Depths

When you fight the Warden, the vibrations he is making are actually making sounds so when you hit him you can hear those vibrations and feel damage. So when you fight the Warden with a Trident, because it's metalic, it amplifies the vibrations of the Warden and when the waves of that vibration get to you, you experience the same damage you gave him. And there's an Achievement: "Kill a Warden on one hit, and survive" - "The Two Deep Depths". To unlock it you'ld have to make a Channeling Trident (and some other enchantment that you can only find in books in 0.3% of sea monuments), have every single effect that makes you stronger, have a turtle master potion, have a full durability shield, have a fully enchanted Netherite armour, have an enchanted golden Apple efect, and shoot him. The Vibrations will break all your armor, set you to half a heart and take all the enchantment off of the Trident. He won't survive. Feel free to edit it a bit