Telemaine's Tangling Tendrils

Vines explode from a point you choose within 60 feet. each creature in a 15-foot radius sphere must make a strength saving throw or be restrained. The area becomes difficult terrain for those hostile to the caster. At the start of each of it's turns, the target can make another strength saving throw. On a success the spell ends on the target.  As an action you can attempt to restrain a creature who is not currently restrained by the spell but is within it's area of effect.  On your turn, restrained creatures move at a rate of 5 feet towards the center and take 1d4 piercing damage, If a creature is unable to move closer to the center it instead takes 1d8 damage. At higher levels damage increases by 1d4 and 1d8 respectively per spell level.