Robots

Robots are entities constructed by humans to serve a variety of purposes. Construction, medical purposes, clean-up, warfare, manufacturing, and so on. They are an integral part of a modern, technology-centered society. They do what needs to be done, without hesitation or concern (beyond pre-programmed safety protocols) for others. Reliable, and efficient.

Sometimes, however, they fall into the same state as their Android cousins. Developing a sense of self, and thinking for themselves. Often this is only the case for artificial intelligences, virtual intelligences, or super advanced machines. Still, it does happen from time to time.

In some other cases, they may short circuit...becoming a rather extreme threat to everyone around them.