Potion of Thunder Shielding

Rare Potion

Liquid Shield. The translucent blue liquid of this potion occasionally turns dark gray and opaque. It tastes exactly like fresh water.
When you drink this potion, you gain resistance to Thunder damage. Puffs of white cloud float around your body. Whenever a creature within 5ft. of you hits you with a melee attack, the shield erupts with a blast of thunder, dealing 2d8 Thunder damage to the attacker. These effects last for 10 minutes.

Variant of
Potion of Shielding