Armor of Cathrys

A protective magical force surrounds you, manifesting as a beautiful, large green fronds which cover you and your gear like a breastplate, and near the shoulders, and center of the chest, a cluster of white blooms. You gain 5 temporary hit points for the duration. If a creature hits you with a melee attack while you have these hit points, the creature takes 5 acid damage, and 1d4 damage over the course of the next 1d4 turns.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, both the temporary hit points and the cold damage increase by 5 for each slot.