I am surprised nobody mentions stupidly smart AI. We can create AI that is capable of self-replicating very fast and fulfilling some goal.
It could start with a noble idea to build a machine to recycle our garbage and use the garbage to build more recycle machines. At the end we can have stupid machines that are perfectly doing their job but because they are capable of replicating and getting better what they do. They determine if they kill human, less garbage is created and thus so less work for them.
At the end they will wipe out us. Because the thing that will kill us doesn't need to be smarter. It needs to be faster and more effective than we are.
It could start with a noble idea to build a machine to recycle our garbage and use the garbage to build more recycle machines. At the end we can have stupid machines that are perfectly doing their job but because they are capable of replicating and getting better what they do. They determine if they kill human, less garbage is created and thus so less work for them.
At the end they will wipe out us. Because the thing that will kill us doesn't need to be smarter. It needs to be faster and more effective than we are.