When attuned to the hammer, the weilder becomes one with the weapon and automatically gains the Great Weapon Master feat if you don't have it already.

Crackling energy and twirling flames course through the head of the hammer. It has 6 charges. After you have landed a hit with the hammer, you can expand a charge to add 2d8 lightning (or Fire) damage to your damage. Charges come back after a long rest or a short rest spent meditating in stormy weather or close to a volcano's caldera.

You can spend 2 charges when throwing your weapon to travel with it. You fly to the location that the hammer hits, no longer than 60 feet.

You can spend 3 charges to cast the spell Fireball at 3rd level. You can expend more charges to cast the spell at a higher level, expanding one charge per spell level

You can spend all 6 charges to create an enormous pillar of fire. It is a 20ft pillar centered on a point you can see within 120ft. Each creature cought in this radius must succeed on a Dexterity saving throw (8+Prof+Cha) or suffer 12d6 of fire damage, half as much on a save.

If you spend all charges on the hammer, roll a d20. On a 5 or lower, it takes 3 days for the charges to reset.

You cannot be disarmed when weilding this weapon.

If the attuned does not have the hammer in his hands, he can spend a bonus action to call it back. The hammer has a travel speed of 150ft.

Weilded by lightning,

Awakened in fire.

Wind will make it sing,

And earth reveal his desire.

Can the worthy fulfill his destiny?

Or perish, along with humanity.