Lead Mushrooms are metallic Mushrooms made of lead. Though they help Mario by making him be resistant to nuclear radiation and allow him to walk on molten plutonium, they kill Mario since lead is a toxic metal. Even though Mario dies, his corpse is resistant to radioactive materials. This is good, because Nobody wants Mario's corpse to be radiaoactive. Honestly, radioactive dead people are too dangerous to be buried, and it is a crime to not bury a dead person. Lead Mushrooms are perhaps more toxic than Poison Mushrooms. Not even Chuck Norris, Evil Guy, Joseph Stalin, or a Goomba is able to eat these.