To attune to this scabbard, one must be in a life-or-death situation. Roll a 1d100 on your turn, to determine if you can feel the scabbard's magic, must get a 70 or higher. You still do not draw upon the blade just yet, another 1d100 has to be rolled to determine if you draw out a blade. This roll must be an 80 or higher. Continue until you achieve these rolls.

This scabbard appears to be empty, and any blade that is sheathed within the blade, that isn't produced from the scabbard, disintegrate upon entering.

This scabbard can manifest a bladed weapon from a dagger to a colossal great sword. Roll an additional 1d8 to determine which magical effect is upon the blade as it is drawn. Default blade is a long sword.

1) Flame Blade (4d12) Fire Damage - Take an additional 2d6 fire damage for 1d4 rounds
2) Frost Blade (4d12) Frost Damage - Movement speed is reduced to 0 until the start of your next turn
3) Poisoned Blade (4d12) Poison Damage - Constitution saving throw (DC13) poisoned until the start of your next turn
4) Celestial Blade (4d12) Radiant Damage - Massive AOE burst, every creature within 20 feet of the creature hit with this attack, will take an additional 2d6 radiant damage and turn CR 1/2 and lower undead
5) Phasing Blade (4d12) Vicious on a 16 and up - Outside of combat, can be used to cut anything 
6) Soul Blade (2d12) + (2d12) Force and Necrotic Damage - Prevents resurrections from anything short of a wish spell
7) Darkened Blade (Blinded) Blind for 1 minute - Silenced and deafened for the minute too
8) Stone Blade (4d12) Bludgeoning Damage - Stones drop around the creature, creating difficult terrain for 10 feet

You can also use the scabbard as an improvised weapon, make an unarmed attack + your Strength modifier + 3

This scabbard shields you with its own magical aura, you gain immunity to the conditions of frightened and charmed and can't be put to sleep by magical means

 Can also cast Disintegrate 3 times a day, recharges with a long rest. 
Point the scabbard at an enemy and focus on the spell.

Part of the Set of Wonders

Notes: Damage: Slashing, Damage: Slashing, Weapon Property: Versatile, Natural Weapon: Slashing, Natural Weapon: Slashing, Immunity: Charmed, Immunity: Frightened, Immunity: Magical Sleep, Blinded, Deafened, While in the midst of battle, life-or-death situation., Damage, Utility, Combat