Aqua Bolt

You hurl a mote of chilling water at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d8 cold damage. On a successful hit, the target must make a Constitution saving throw against your spell DC, or half their movement reduced by 5ft. 

This spell's damage increases by 1d8 and the movement reduction increases by 5ft when you reach 5th level (2d8) and (10ft), 11th level (3d8) and (30ft), and 17th level (4d8) and (40 ft).