Drag into Earth

You call forth the roots of the nearby trees  and plant life to reach up and attempt ensnare one creature within 30 feet of you. The creature must succeed on a DC 16 dexterity saving throw or be come restrained by the roots. At the end of the creature's turn the creature remains restrained it is pulled deeper into the earth. It can attempt a strength check of DC 18 or higher at the start of each of its turns to break free. If it succeeds the creature is no longer restrained, if it fails it will sink one foot per round it remains restrained. If the creature is waist deep, it must take its action to pull itself out of the ground. If it is chest deep it it must make a strength check to pull itself out of the ground. If it neck deep it must be assisted in its escape from its earthly bonds. If it completely buried it will have 1+ the creatures constitution modifier's minutes of air before suffocating to death.