Greater Silver Sword
Weapon (greatsword), legendary (requires attunement by a creature that has psionic ability)
- Damage: 2d6 slashing
- Properties: Heavy, Two-Handed
- Weight: 6.0 lbs.
This magic weapon grants a +3 bonus to attack and damage rolls made with it. While you hold the sword, you have advantage on Intelligence, Wisdom, and Charisma saving throws, you are immune to being charmed, and you have resistance to psychic damage. In addition, if you score a critical hit with it against a creature’s astral body, you can cut the silvery cord that tethers the target to its material body, instead of dealing damage.
Source: Mordenkainen’s Tome of Foes p. 89