Africanized bees, better known as killer bees, are a subspecies of honey bee and are very dangerous, unlike the honey bee, which is docile unless provoked. Let's get into how they came to bee.
History
Scientist Warwick E. Kerr was attempting to crossbreed honey bees from Europe and Southern Africa so that they would make more honey. It was also to attempt to make them more adaptable to tropical conditions thus being more productive. The crossbred species was then moved to Brazil to be tested, where they were noted to be particularly defensive. However, before the bees could be tested, a visiting bee keeper noticed that the queen bees were interfering with the worker bees. So he let them out resulting into 26 swarms of Africanized