Byes

Speak the Byes, the word radiating out in the direction you point. Any creature in the 30-foot cone must make a Wisdom Saving Throw. On a failed save, they take 3d6 Psychic damage, and are cursed with the Byes. Every word they speak must begin with 'B', or take 1 Psychic damage per word spoken without the word. Take half damage on a successful save.

Using a Higher-Level Spell Slot. The damage increases by 1d6 and curse lasts 1 hour longer for each spell slot level above 2.