Episode 17 brings two very different, but equally strange, topics. Polybius is a video game that popped up in just a handful of arcades in the 80's before swiftly disappearing... was it used as some kind of mind control device? The Taos Hum -- more generally called The Hum, as it exists all over the world -- is a low-frequency rumbling, whirring, or buzzing that people called "hearers" experience. Is it a result of secret government experiments or equipment? Is it a bizarre natural phenomenon? Or is it all in their heads?