Thousand Thundering Birds

As an action, you gather primordial lightning into your hand; the high concentration of electricity produces a sound reminiscent of many birds chirping.

You must have one hand free to cast this spell. You can make an immediate dash action towards a target in a straight line. You are not obstructed by difficult terrain or provoke any attacks of opportunities during this dash. 

Make a melee spell attack with an advantage. If you already have an advantage, you double the number of your rolls. 

On a hit, it takes 2d8 piercing and 4d12 primordial lightning damage. The spell rolls a critical on 18 to 20 or if your attack roll is 10 more than the target's AC. The critical multiplier is x2. If you attack a creature that is surprised, cannot move or has not taken an action since the start of the combat, you gain an advantage and roll maximum damage. 

The critical attack range is increased by the same amount if you have an ability which increases you attack's critical range. 

At every level above the 3rd the dash range increase by half your movement speed and the damage increases by 1d6 + 1d12. At level 6, the critical multiplier increases to x2.5 rounded down. At level 9, the critical multiplier increases to x3.