Electroshield

Crackling streaks of lightning dance around your body for the duration, shedding flickering dim light for 10 feet. You can end the spell early by using a bonus action to dismiss it.

The lightning provides you with a positive or negative shield, as you choose. The negative shield grants you resistance to acid damage, and the positive shield grants you resistance to lightning damage.

In addition, whenever a creature within 5 feet of you hits you with a melee attack, lightning arcs out and strikes the attacker. The attacker takes 2d8 lightning damage from either shield form.