Nightmare (5e Equipment)
From D&D Wiki
Weapon (halberd), rare (requires attunement)
A pitch black weapon imbued with the captured terror of its victims. This chillingly cold blade releases a baleful aura when wielded that makes weaker foes tremble.
Nightmare feeds off of the fear and terror of its victims. Any melee attack made against frightened creatures with this weapon deals an additional 2d6 psychic damage.
As an action you slam Nightmare on the ground and expend one charge to release Nightmare's accumulated baleful aura in full force. Every creature of your choice with 30ft. radius that can see or hear you must make a DC (DC = 8 + proficiency bonus + your Charisma modifier) Wisdom saving throw or be frightened until the start of your next turn.
Nightmare has a total of three charges and regains 1 charge at midnight.