Alzur's Thunder

A thick, black cloud covering an area of radius 45 ft. covers the sky above a target you can see within range; shortly after, an immense lighting bolt strikes. The spell fails if there's no room for the cloud above the target (for example, if you're casting this spell inside a house where the cloud won't fit). If the target is a creature, it must make a Dexterity saving throw. The creature takes 12d6 lightning damage on a failed save and half as much damage on a successful one. If it fails the saving throw, any equipment it was wearing is immediately burned to ashes - or melted away if it was made of metal. Any creature that dies because of this spell's damage has its body incinerated. If the target is an object instead, it takes 12d6 lightning damage and, if destroyed, is burned to ashes - or melted away if it was made of metal.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d6 for each slot level above 5th.

We stand not the slightest chance of incanting a spell so complex as Alzur's Thunder. It is claimed Alzur had a voice like a hunting horn and the diction of a master orator.