You fire a 5 ft. sphere of exploding electricity out from your palms and away from you in a 30 ft. line. The sphere produces bright light in a 15 ft. radius around it and dim light for another 15 ft., and is mostly insubstantial; it passes through creatures and most objects, but is blocked by 2 feet of rock, 2 inches of any metal other than lead, or a thin sheet of lead. Each creature that comes into contact with the sphere must make a Dexterity saving throw. On a failed save, a target takes 2d6 lightning damage and can’t take reactions until the end of your next turn. On a successful save, a creature takes half damage. On each subsequent round after initially casting thunderbolt, you can use your bonus action to move the sphere up to 20 ft. in a direction of your choice, but it must end in a location that's further away from you.
At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the amount of damage dealt increases by 1d6 for each slot level above 2nd.
* - (a rod of amber)