A beam of crackling, blue energy lances out toward a creature within range, forming a sustained arc of lightning between you and the target. Make a ranged spell attack against that creature. On a hit, the target takes 1d12 lightning damage, and on each of your turns for the duration, you can use your action to deal 2d12 lightning damage to the target automatically. This damage increases by 1d12 every round the spell is active. The spell ends if you use your action to do anything else. If the target is outside the spell's range or your line of sight at the start of your turn, you must make a DC 15 spellcasting ability check, ending the spell on a failure. If the target is ever more than 60 feet away from you, or behind solid full cover, the spell ends.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the initial damage increases by 1d12 for each slot level above 1st.