Essence of Rage (Patreon)

Potion, rare

This bubbling red liquid is always warm and tastes of iron and bitter raisins. You can drink this potion as a bonus action. When you do, you enter a rage that lasts for 1 minute or until you're knocked unconscious. This rage grants you the same effects as a 1st-level barbarian's class feature with the following exception: if you end your turn and you haven't attacked a hostile creature since your last turn or taken damage since then, you take 1d4 psychic damage and your rage does not end. You can enter this rage even if you're wearing heavy armor. 

You should never bottle up your emotions. Especially your anger.