Coulomb's Tether

A beam of energy jolts out toward a target creature within range. Make a ranged spell attack against the target creature. On a hit, the target takes 2d8 lightning damage and a thin tether that faintly crackles with small arcs of lightning forms between you and the target. While tethered this way, you can use your action to deal 2d8 lightning damage to the target automatically then each creature between you and the target must make a Dexterity saving throw, taking that much damage as well on a fail save. The spell ends if you do not use your action to reactivate this ability, if the target is ever outside the spell’s range, or if it has total cover from you.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, both the initial and activation damage increases by 1d8 for each slot level above 2nd.