Sudden Exertion

Your bugbear nature allows you to fly into sudden frenzied rages that exert all of your energy at once. Whenever you make an attack you can fly into one of these frenzies for an amount of turns equal to your constitution modifier (minimum of 1) or until you are incapacitated. When it ends you suffer from one level of exhaustion. Once on each of your turns while in one of these frenzies and make an attack you can cause the attack to deal an extra amount of damage in an amount of d6s equal to half your proficiency bonus.