Dragonstorm

You create a Huge dragon-shaped plane of thunderclouds above you, facing towards your line of sight. As a bonus action on your turn, you can command the dragon to fly forward, covering feet equal to your current Speed per three seconds. When it hits a solid barrier larger than it, it dissolves into mist. Any creature that touches the dragon (released or not) must make a Dexterity saving throw. It takes 5d10 Lightning damage and 5d10 Thunder damage on a failed save, or half as much on a successful one. Additionally, when you cast this spell, a pair of dragon wings manifest on your back, and you gain a flying speed equal to your current speed. The wings last for 3d4 hours. At higher levels: When cast with a spell slot above 7th, the damage increases by 2d10 per level after first. Additionally, the wings last for an additional 1d4 hours.