Thunderbolt

You hurl a bolt of thunder at the target, doing 2d6 Thunder damage and deafening the target if the target has 12 or less constitution. A target already deafened takes 1d6 extra damage.

The constitution required to not get deafened on hit increases to 13 at 6th level, 14 at 11th level, 15 at 15th level, and 16 at 18th level. The damage also increases to 3d6 at 8th level, 4d6 at 12th level, 5d6 at 15th level, and 6d6 at 19th level.