Radiation isn't all bad in Fallout 76: it can make your DNA more interesting by causing you to mutate. While Fallout 76 mutations may give some of your stats a few benefits, it will also penalize others. In the video above (also on YouTube), I contract the marsupial mutation, which lets me jump much higher but also makes me dumber, like some sort of stupid, heavily-armed kangaroo.
Mutations will occur randomly. When you're exposed to radiation via proximity, eating and drinking, or combat, there's a 5% chance you'll mutate for every 5 HP irradiated. Mutations will remain with you even if you die and respawn. You can also obtain mutation serums from a vendor in Whitespring and from The Enclave's science division, though they're pretty pricey.
When you take RadAway, there's a chance it will cure your mutation in addition to removing rads from your system. There's also a Fallout 76 perk called Starched Genes, which can do two things depending on when you equip it: prevent you from mutating in the first place, or—if you have mutated already—prevent you from curing your current mutation via RadAway, which is useful if you've found a mutation you like and want to keep it. There's also a perk called Stranger in Number, which increase the positive aspects of your mutation by 25% if you have a mutated teammate.
Here's every Fallout 76 mutation, and their pros and cons:
Chameleon
Pro: Grants invisibility...
Con: ...as long as you don't have a weapon equipped, and don't move
Marsupial
Pro: +20 carry weight, added jump height
Con: -4 intelligence
Bird Bones
Pro: +4 intelligence, falling speed is slower
Con: - 4 strength
Egg Head
Pro: +6 intelligence
Con: -3 strength, -3 endurance
Healing Factor
Pro: +300% health regeneration
Con: -55% chem effects
Talons
Pro: + 25% damage using unarmed attacks
Con: -4 agility
Empath
Pro: Teammates take -25% damage
Con: Player with mutation takes +25% damage
Scaly skin
Pro: +50 damage and energy resistance
Con: -25 action points
Eagle Eyes
Pro: +25% to critical damage
Con: -4 strength
Grounded
Pro: +100 energy resistance
Con: -20% energy damage dealt
Herbivore
Pro: Vegetables provide 2x normal benefit
Con: Meat provides zero benefit
Carnivore
Pro: Meat provides 2 times normal benefit
Con: Vegetables provide zero benefit
Adrenal Reaction:
Pro: Increased weapon damage while at low HP
Con: -50 Max HP
Electrically Charged
Pro: Chance to shock melee attackers
Con: Small amount of damage done to player
Herd Mentality
Pro: All SPECIAL stats +2 while in a group
Con: All SPECIAL stats -2 while playing solo
Plague Walker
Pro: Diseases act as a poison aura against enemies
Con: You still suffer the negative effects of the disease
Speed Demon
Pro: +20% to movement speed and reloading
Con: +50% drain to hunger and thirst while moving
Twisted Muscles
Pro: +25% melee damage, increased chance to ripple limbs
Con: -50% gun accuracy
Unstable Isotope
Pro: 10% chance to release radiation when struck by melee attack
Con: Small amount of damage done to player
