Entropic shield

Your body is surrounded by creeping energy, or a bright sunny light for the duration, shedding bright light in a 10-foot radius and dim light for an additional 10 feet. You can end the spell early by using an action to dismiss it.

The spell provides you with a bright shield or gloomy shield, as you choose. The bright shield grants you resistance to necrotic damage, and the gloomy shield grants you resistance to radiant damage.

In addition, whenever a creature within 5 feet of you hits you with a melee attack, the shield erupts with light. The attacker takes 2d8 radiant damage from a bright shield or 2d8 necrotic damage from a gloomy shield.