Balzorth’s Scepter of the Storm

"[...] And the Storm God Balzorth struck the ground with his scepter, causing a reverberation that shook the entire Material Plane and beyond. A destructive storm fell upon the world, disintegrating all that was evil and purifying the righteous and the pure of heart. Having done this, Balzorth withdrew from the Material Plane and was never heard from again."
— Mysterious Sage, Tome of Ancient Times

Description
Created during the War of the First Thunder, the scepter was carved from a long-forgotten material, infused with the fury of the storm within the Elemental Plane of Air. Approximately five feet long, the scepter is carved from a single block of translucent material, within which a perpetual storm of frantically flickering lightning is trapped. The hilt is wrapped in ancient blue dragon hide, warm to the touch and constantly crackling with static discharge. When the scepter is raised, clouds instantly gather above the wielder and the air vibrates with the sound of distant thunder. It is not heavy, yet the wielder feels the crushing "weight" of divine responsibility.

Properties
This scepter can be wielded as a magic staff that grants a +3 bonus to attack and damage rolls made with it. While holding it, you gain a +3 bonus to spell attack rolls.

The scepter has 100 charges for the following properties. It regains 6d8 + 3 expended charges daily at dawn. If you expend the last charge, roll a d20. On a 20, the scepter regains 1d12 + 1 charges.

Spells. While holding the scepter, you can use an action to expend some of its charges to cast one of the following spells from it, using your spell save DC and spellcasting ability:

Thunder and Lightning Infusion. When you hit with a melee attack using the scepter, you can expend 1 charge to deal an extra 2d6 lightning damage and 1d6 thunder damage to the target. Additionally, you can cause the scepter to emit a crack of thunder audible out to 300 feet (no action required). The target must succeed on a DC 17 Constitution saving throw or be stunned until the end of your next turn.

Storm Form. You can expend 40 charges to transform into a storm cloud; your equipment merges into your new form. You gain a flying speed of 60 feet, but lose all other speeds. On your turn, you can only take the Dash action. You gain immunity to all damage types except psychic, force, and thunder. Wind can move you at four times the normal rate, and you can pass through the space of other creatures.
Any creature within 10 feet of you must make a Dexterity saving throw against your spell save DC. On a failure, it is struck by lightning and takes 2d10 lightning damage. If you occupy another creature's space, it has disadvantage on the save and, on a failure, takes an additional 2d10 lightning damage and 2d10 thunder damage. As long as a creature remains in your space, it is blinded and deafened.

Balzorth’s Hyper-Destructive Storm. You can expend all remaining charges (minimum 50) to cast the 10th-level spell of the same name. Every 5 charges spent beyond the initial 50 increase the duration of the spell by 1 round. If all 100 charges are used, the duration lasts for 5 hours.