Aldous's Crystal Blade

You recite an incantation while holding the hilt, ice particles surround your hand and coalesce in the hilt forming an elegant crystal blade. This magic sword lasts until the spell ends. It counts as a simple melee weapon with which you are proficient. It deals 3d8 cold damage on a hit and has the finesse, light, and thrown properties (range 20/60).

If you drop the weapon or throw it, it remains in the new location. However, other creatures are unable to benefit from the weapon's magic, functioning as an ordinary short sword for them. Thereafter, while the spell persists, you can use a bonus action to cause the sword to reappear in your hand.

In addition and as a bonus action, you can end the spell to shatter the weapon. Ending the spell this way releases the weapon's magic in a blast of cold energy that affects each creature in a 5-foot-radius sphere centered on the weapon's location. Creatures in the area take 3d6 cold damage on a failed DEX saving throw, or half as much damage on a successful one. Alternatively, you can dismiss the spell anytime without causing the blade to shatter (no action required).

At Higher Levels. When you cast this spell using a 5th- or 6th-level spell slot, the hit damage increases to 4d8 and the shattering blast damage increases to 4d6. When you cast it using a spell slot of 7th level or higher, the hit damage increases to 5d8 and the shattering blast damage increases to 5d6.