New Magic Weapon: Bolt of Zeus, is it balanced or OP?

[DracoKnight]

Bolt of Zeus
very rare, requires attunement
Greatsword, finesse
This magic item is a +2 weapon that looks like the hilt of a longsword with the blade of a dagger. Normally it will deal 2d4 piercing damage. As an action you may activate a magical blade of lightning that materializes around the dagger blade. After you have activated the blade, the Bolt of Zeus does 2d6 lightning damage. On an attack with the blade active, you may instead of making a melee attack with the +2 property, make a ranged attack with that deals 1d4 + 1d6 lightnig damage. The range of this attack is 30ft, and the attack targets a single creature. This property dispels the blade and you must wait two turns before you can reactivate it.

[BRKNdevil]

A few comments and questions.
Why did you envision Zeus's bolt as a Greatsword when that weapon wasn't even created by that point? Most people (fiction writers) have it as a regenerating Javelin or shortsword (as a gladius). On that note, they have a javelin of lightning (DMG 178). And finally, just make the ranged attack either 2d4 or 2d6 and keep it simple. Past that it is either at the level of a very rare item or at least within the bell curve of power for that rarity i think.

[DracoKnight]

Storm Sword
very rare, requires attunement
Greatsword, finesse
This magic item is a +2 weapon that looks like the hilt of a longsword with the blade of a dagger. Normally it will deal 2d4 piercing damage. As an action you may activate a magical blade of lightning that materializes around the dagger blade. After you have activated the blade, the Storm Sword does 2d6 lightning damage. On an attack with the blade active, you may instead of making a melee attack with the +2 property, make a ranged attack with that deals 2d6 lightning damage. The range of this attack is 30ft, and the attack targets a single creature. This property dispels the blade and you must wait two turns before you can reactivate it.

[BRKNdevil]

That sounds good to me. now you just have to see what other people think.

[JNAProductions]

Seems a bit weak, actually. It's a +2 greatsword with lightning damage instead of slashing and a weak ranged attack.

No better than a +2 greatsword, really, and (AFB at the moment) if a regular +2 weapon is only rare, it could use more power, not less.

That being said, I don't like +X weapons. I'd just focus on more special effects, less numbers.