Dragon Render (5e Equipment)
From D&D Wiki
Weapon (any sword), legendary (requires attunement)
This sword is the bigger, badder, and much rarer cousin of the dragon slayer. You gain a +2 bonus to attack and damage rolls made with it. When you hit a dragon with it, the dragon takes an extra 6d6 damage of the weapon's type. For the purpose of this weapon, "dragon" refers to any creature with the dragon type, including dragon turtles and wyverns.
Dragon Dread. Dragons can instinctively sense the presence of this weapon and fear its power; When a dragon comes within 120 feet of the sword, it must make a DC 17 Wisdom save or be frightened of it for 1 minute. A dragon can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a dragon's saving throw is successful or the effect ends for it, the dragon is immune to being frightened by the dragon render for 24 hours.
Curse. This sword is cursed, and being attuned to it extends the curse to you. While attuned to the sword, every dragon within 1 mile of you is aware of your presence. While you are within 120 feet of a dragon, the dragon automatically knows your exact location, even if you are hidden from it or invisible. You also have disadvantage on ability checks to convince dragons of peaceful or friendly intent.