Chidori Blade

You evoke a Lightning blade in your free hand. The blade is similar in size and shape to a rapier, and it lasts for the duration. If you let go of the blade, it disappears, but you can evoke it again as a Bonus Action.

As an attack action, you can make a melee spell attack with the Lightning blade. On a hit, the target takes Lightning damage equal to 2d8 plus your spellcasting ability modifier. Target also makes a Con save, on a failure the target is stunned until the end of your next turn. 

The Lightning blade sheds Bright Light in a 10-foot radius and Dim Light for an additional 10 feet. It also chirps and crackles like a thousand birds.

The damage increases to 4d8 at level 5, 6d8 at level 10, 8d8 at level 15, and 10d8 at level 20.