Sumarbrander (5e Equipment)
From D&D Wiki
Weapon (shortsword), legendary (requires attunement)
Sumarbrander, referred to as Jack, is a shortsword with a gold-colored, 30 inch long blade. His handle is wrapped in leather, and has a simple, polished oval as a pommel. Down the center of the blade, there is a wide, shallow fuller. In the fuller, there are Norse runes which are a silver color. The runes look as if they were inlaid while being forged. You have a +4 bonus to attack and damage rolls with this magic weapon.
Let Me Go. As a bonus action, you can let go of Jack and tell him to attack a creature you can see within 60 feet of you. He can fly over or around obstacles, but will not go through them. Once he arrives at his target, he attacks for 4d6 piercing damage. The attack bonus for this is your Strength modifier or your Dexterity modifier + your proficiency bonus. He then comes back to you. If the attack hit, once you grab his handle, you suffer one level of exhaustion. You must wait 1 hour before using this effect again.
World Traveler This magical weapon may cut through reality to make a portal to another plane. As an action, you may cast the plane shift spell without needing material components. The weapon regains use of this effect at dawn and dusk.