Mordenkainen's Lost Notebook

Heart of Earth

4-level Transmutation

While heart of earth is in effect, you have advantage on saving throws to avoid being pushed, pulled, or knocked prone. In addition, you gain 20 temporary hit points. Furthermore, while heart of earth is active, you can use your reaction to cast the stoneskin spell on yourself. This benefit lasts for 1 minute. Once the stoneskin effect has been used, heart of earth ends. If heart of earth is active on you at the same time as heart of air, heart of fire, and heart of water, you become immune to extra damage from critical hits and sneak attacks.