Robots can pose -- or can appear to pose -- a threat to life, property, and privacy. May a landowner legally shoot down a trespassing drone? Can she hold a trespassing autonomous car as security against damage done or further torts? Is the fear that a drone may be operated by a paparazzo or a peeping Tom sufficient grounds to disable or interfere with it? How hard may you shove if the office robot rolls over your foot? This paper addresses all those issues and one more: what rules and standards we could put into place to make the resolution of those questions easier and fairer to all concerned. The default common-law legal rules governing each of these perceived threats are somewhat different, although reasonableness always plays an important role in defining legal rights and options. In certain cases -- drone overflights, autonomous cars, national, state, and even local regulation -- may trump the common law. Because it is in most cases obvious that humans can use force to protect themselves against actual physical attack, the paper concentrates on the more interesting cases of (1) robot (and especially drone) trespass and (2) responses to perceived threats other than physical attack by robots, notably the risk that the robot (or drone) may be spying -- perceptions which may not always be justified, but which sometimes may nonetheless be considered reasonable in law. We argue that the scope of permissible self-help in defending one's privacy should be quite broad. There is exigency in that resort to legally administered remedies would be impracticable; and worse, the harm caused by a drone that escapes with intrusive recordings can be substantial and hard to remedy after the fact. Further, it is common for new technology to be seen as risky and dangerous, and until proven otherwise drones are no exception. At least initially, violent self-help will seem, and often may be, reasonable even when the privacy threat is not great -- or even extant. We therefore suggest measures to reduce uncertainties about robots, ranging from forbidding weaponized robots to requiring lights and other markings that would announce a robot’s capabilities, and RFID chips and serial numbers that would uniquely identify the robot’s owner. The paper concludes with a brief examination of what, if anything, our survey of a person's right to defend against robots might tell us about the current state of robot rights against people.