Weapons of the Shifting Void (Ostal)

You weave together threads of the shadowfell's essence to create a shifting weapon of shadowsteel. This magic weapon lasts until the spell ends. It can take the form of any one handed melee weapon with which you are proficient except it deals necrotic damage instead of it's normal damage type and deals one additional weapon die worth of psychic damage on a hit.

While wielding this weapon, you can attempt to hide even when you are lightly obscured by dim light or darkness and you can stay hidden while approaching a creature as long as your movement doesn't take you into an area of bright light.  When you are hidden from a creature and miss it with this weapon attack, making the attack doesn't reveal your position and you may choose to have the weapon disappear without making a sound. If you do so, you can choose to immediately use your reaction to reroll the attack with advantage as the weapon reappears in your grip. 

While concentrating on this spell, you can summon a new shadowsteel weapon using your bonus action.

At Higher Levels. When you cast this spell using a 3rd- or 4th-level spell slot, the bonus psychic damage increases to two weapon dice and the weapon you summon gains the light property. When you cast it using a 5th- or 6th-level spell slot, the bonus increases to three additional weapon dice and the weapon you summon can have the versatile property. When you cast it using a spell slot of 7th level or higher, the bonus increases to four additional weapon dice and the weapon can have the two handed property.