Robots run amok have occasionally maimed or killed industrial workers, giving German researchers cause to wonder about a future where humans host robots in every home. In their study, the BBC reports, a robot arm was programmed to strike, stab and puncture using an array of household tools that included a steak knife, kitchen knife, scissors and screwdriver. Stabs and cuts inflicted on a silicone lump and the leg from a dead pig were deemed potentially lethal.