Harm

You unleash a virulent disease on a creature that
you can see. The target makes a Con save. On a
failure, it takes 14d6 necrotic damage, or half as
much on a success. The damage can't reduce the
target's HP below 1.
If the target fails the save, its maximum HP is
reduced for 1 hour by an amount equal to the
necrotic damage it took. Any effect that removes
a disease allows a creature's HP maximum to
return to normal before that time passes.