Earth Anchor

Reaction trigger: You are forced to make a Strength or Dexterity saving throw

The earth wraps around your feet and you become anchored to the ground for the duration or until you willingly move. While you are anchored gain advantage on all strength or dexterity saving throws, including the triggering saving throw, no effect may move you or knock you prone against your will. You may act as three quarters cover against the triggering effect and all subsequent attacks while this spell is active.