One step up from pit traps are landmines. They kill or maim an estimated 2,000 people a month, autonomously. There's one active landmine for every 52 people in

One step up from pit traps are landmines. They kill or maim an estimated 2,000 people a month, autonomously. There's one active landmine for every 52 people in the world. They're cheap- the most common ones range in price from $3-$30, but they cost much more than that to remove and about 1 person is killed for every 5,000 mines disabled. They won't hunt you down, but they're invisible and can remain active for decades. We don't need to veer off into speculative sci-fi territory to find autonomous weapons doing terrible things.