Dragon Storm

The skies darken as a dragon made entirely of lightening swoops through the clouds and exhales a laser of lightening in a 20ft line towards the target, then flies back to the heavens. Target and any creatures in the line of fire must roll a Dexterity saving though. On failure they take 5d10 lightening damage and become stunned until the end of their next turn, on success they take 1/2 the damage and don't get stunned.

At 7th or higher increase damage by 1d10 for each level.