5 accessories that give -10%, -20%, -40%, -60% and -80% to each stat respectively, so you can have fights with weaker enemies that felt the way they did when you were in earlier stages of World Tour, without actually having to restart the entire mode from scratch. The 20 to 80% ones don't stack, but the 10% one uses a different perk, so you can pair it with the others to get -30%, -50%, -70% and -90%.

I am aware that those "debuff items" exist, but they are either not enough on their own, only debuff 1 type of attack if you want the effect to be stronger, and you have to activate it every single battle. This could give you a challenge without needing to farm for an item just to weaken yourself.