Primal Path: Path of the Madman
Barbarian strong! But barbarian not invincible... MUNDO IS HERE TO SAVE THE DAY.
Goes where one pleases
At 3rd level when you select this primal path, your pure constitution actively keeps you on your feet. You can enter into a rage as a reaction, and whenever you're in a rage and you're immune to being; knocked prone, stunned, or your actions or movements are restricted in any way.
Also, Whenever you go into a rage you heal for 3d6 + your barbarian level. At 10th level this healing is increased to 6d6 + your barbarian level.
Heart Zapper
At 6th level, your heart beats so fast that it generates massive amounts of electricity. This ability activates while your rage is active. For the duration of your rage, you deal 2d12 lightning damage to enemies within 10 feet of you and you heal for half the damage dealt.
At the start of their turn they must make a Constitution saving throw against your Constitution Ability Score or have their movement speed reduced by half for that turn of combat. At the end of your rage your heart lets out a discharge pulse, dealing 4d8 lightning damage to all surrounding enemies within 20 feet, tripling damage towards constructs.
Blunt Force Trauma
At 10th level, You fight with no regard for health, yours or your enemies. You gain an immunity to bludgeoning damage, and resistance to piercing and slashing damage out of your rage. While you rage you can add half your barbarian level (rounded down) to any attack made with a bludgeoning weapon. Critical hits made with bludgeoning weapons deal an extra 4d10 + your barbarian level in bludgeoning damage and send an enemy flying back up to 30 feet away if they are large or smaller.
Titanic Hydra
At 10th level, in your raging fury strength is increased ten fold. While you're raging, once per turn, as a bonus action, your can swing your weapon so fast and hard that every enemy within a 30-foot cone in front of you, mast make a Dexterity saving throw against your Constitution Ability Score, taking 10d8 bludgeoning damage on a failed save, and half as much on a successful save.
Maximum Dosage
At 14th level, your vitality knows no bounds. You double your proficiency bonus to Constitution saving throws and you gain proficiency in survival if not already proficient. While you rage, you double any healing coming towards you. You may choose to use your rage healing for your nearest ally instead of yourself at the start of your rage.