Sea Witch's Blade

This slim, slightly curved blade has a ghostly sheen and a wickedly sharp edge. You can use a bonus action to speak this magic sword's command word (“memory”) and cause the air around the blade to shimmer with a pale, violet glow. This glow sheds bright light in a 20-foot radius and dim light for an additional 20 feet. While the sword is glowing, it deals an extra 2d6 psychic damage to any target it hits. The glow lasts until you use a bonus action to speak the command word again or until you drop or sheathe the sword. When a creature takes psychic damage from the sword, you can choose to have the creature make a DC 15 Wisdom saving throw. On a failure, you take 2d6 psychic damage, and the creature is stunned until the end of its next turn. Once used, this feature of the sword shouldn't be used again until the next dawn. Each time it is used before then, the psychic damage you take increases by 2d6.