Horrifying 'killer bees' spreading across 13 US states and can sting thousands of times in short period

'Killer' bees are now spreading across 13 US states and are slowly spreading northward, attacking people, livestock and pets along the way. "Killer bees" first made headlines in the 1990s when they began to appear in the United States. As climate change raises temperatures around the world, the killer bees may soon be able to survive in even more US states.