Okay picture this, a small town in rural Russia, think Charnable but bigger. The people withing a ten mile radius are veporized completely those in a 50 mile radius die of the heat or radiation or both. The wind picks up and spreads the ashes of those hunndreds vapor, getting in to the air and water supply, farms. So we continue on, eating, drinking, sleeping, and breathing in the toxic dust. If we had geiger counters they would be steadily rising, thousands of people die mysteriosly, mostly the old and the very very young, but those who didn't die slowly adapt, there skin becomes rougher and shocks you it also becomes a pale greenish color, their body temperature becomes boiling and they grow large nails and sharper teeth, their digestive system turns slowly carnivorous and every living thing save for plants become these hideous dinosaur zombie people bent on satisfying an unsatisfiable hunger for meat and blood, the creatures start waring fangs and claws glint and flesh is torn and ripped, the creatures resorting to cannabalism very often, animals don't cut it, nothing cuts it, and childbirth is excruciatingly painful, the baby rips through your stomach and feeds on your corps. Even though childbirth is possible, humans and animals are unsatisfied, they never would be, there stomach digests everything but never has enough so the stomach slowly tears the flesh from your insides and eat you alive. Everything dies, except for plants and single-celled organism, and the planet is left to reevolve.