Imagine this: You're the most advanced computer ever built, capable of sentient thought, and producing endless waves of evil mechanical soldiers, and you do this all in another day's work of wiping out the remains of the human race, when all of the sudden Christian Bale pops out of a hole in the ground and blows up your CPU. How annoyed would you be? Fortunately for you, you invented time travel earlier that day, so it might be convenient to send back one of your so called "Terminators" back in time to kill this bloke when he was young. Better still why not send your robot buddies back further to kill his mom instead? Easier still, why not finally make yourself a self made machine?