Threads of Fate

You reach out to one creature you can see within range, binding it with ethereal threads. The target must succeed on a Wisdom saving throw or take 1d8 radiant damage and its speed is reduced by 10 ft until the end of its next turn. 
If the creatures speed is already reduced, it instead takes 1d12 radiant damage and its speed becomes 0 until the end of its next turn.

The spell’s damage increases by one die when you reach 5th level (2d8 or 2d12), 11th level (3d8 or 3d12), and 17th level (4d8 or 4d12).