El Kabong

The musical instrument you have played is imbued with the spirit of Townshend and Bleredd, the god of metal. For the duration, you can use your spellcasting ability instead of Strength for the attack and damage rolls of melee attacks using your musical instrument, the weapon's damage die becomes a d8 and Versatile if you can reliably hold it with two hands. The weapon also becomes magical and is indestructible by any physical means. The spell ends if you cast it again or if you let go of the weapon.

If you miss an attack with your instrument while the spell is active, you can use a Reaction to automatically score a critical hit. However, the instrument breaks beyond repair immediately after the hit.