Brutal Basil Hexmallow

Marshmallow Magic This marshmallow has a bold and herby basil flavor. it is dusted with a basil infused sugar.
  You can use a bonus action to eat this marshmallow, when you do, your abilities, attacks and spells ignore any resistance to Bludgeoning, Piercing or Slashing damage a target may have until you finish a long rest. However, for the duration you also are vulnerable to Bludgeoning, Piercing and Slashing damage. If you are resistant, you lose the resistance. If you are immune, you become resistant. For the duration, you cannot gain the benefits of any other hexmallow.