Cruel Sun

You pull energy from the Higher Planes to create a ball of energy that burns like a small star to hurl at your foes. Make a ranged spell attack. On hit, the target takes 1d8 radiant damage and can't regain hit points until the start of your next turn. 

If you hit a fiend target, it also has disadvantage on attack rolls against you until the end of your next turn. 

The spell's damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).