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 chance you'll mutate. 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.
Here's every Fallout 76 mutation we know about so far:
Chameleon: Grants invisibility, as long as you don't have a weapon and don't move.
Marsupial: +20 carry weight, + jump height, -4 intelligence.
Bird Bones: +4 intelligence, falling speed is slower, - 4 strength
Egg Head: +6 intelligence, -3 strength, -3 endurance
Healing Factor: +300% health regeneration, -55% chem effects
Talons: + 25% damage using unarmed attacks, -4 agility
Empath: Teammates take -25% damage, players takes +25% damage
Scaly skin: +50 damage, +50 damage resistance, -25 action points
Eagle Eye: +4 perception, -4 strength
Grounded: +100 energy resistance, -20% energy damage
Herbivore: Vegetables provide 2x normal benefit, meat provides zero benefit
Carnivore: Meat provides 2x normal benefit, vegetables provide zero benefit