weakness curse

if you get hit by this spell your armor goes down [ roll 1d6 and the number it lands on is how much your armor class goes down ] .and your health goes down 3.the only cure to this spell is roll 1d20 and the number has to be above 15 for it to work [ if you try to roll above 15 in a fight and it lands on 16,17,18,19 or 20 you cant use an attack ] .