Dorf’s Paralyzing Lightning

A storm cloud appears in the shape of a cylinder that is 10 feet tall with a 60-foot radius, centered directly above you. The spell functions even if there is no visible sky.

When you cast the spell, a bolt of lightning flashes down from the cloud into you. You can either gain temporary hit points equal to the level you cast the spell at and resistance to lightning damage while the temporary hit points remain, or you can make a ranged spell attack against a creature under the cloud. On a hit, A creature takes 3d10 lightning damage and must succeed on a Constitution saving throw or be paralyzed until the end of its next turn. On each of your turns until the spell ends, you can use a bolt of lightning strikes you and you can choose to gain resistance and temporary hit points (no action required) or make a ranged spell attack.
If you are outdoors in stormy conditions when you cast this spell, the spell gives you control over the existing storm instead of creating a new one. Under such conditions, the spell's damage increases by 1d10.

At Higher Levels. When you cast this spell using a spell slot of 5th or higher level, the damage increases by 1d10 for each slot level above 4th.