Tesseract Tether

You unleash the chaos of the multiverse, creating a harmful wave of energy that roots enemies in their place.

You create a rift in space, launching energy outward in a 60 foot line, 5 feet wide. Creatures in the path must make a Dexterity Saving Throw. On a failed save, creatures take 4d8 psychic damage, and are rooted in place by tendrils that expand from the rift. Successful saves take half damage, and are not rooted. Rooted creatures are considered restrained, and can repeat the saving throw at the end of each of their turns, freeing them on a success. The tendrils remain for one round, in which they cause difficult terrain in their area and lash out at creatures attempting to move through their space, dealing 1d8 psychic damage per 10 ft moved. 

Casting this spell at higher levels causes creatures to take an increased 1d8 psychic damage per level of the spell.