Half a century before Boston Dynamic’s BigDog, GE engineers developed the Cybernetic Anthropomorphous Machine, or Walking Truck. The U.S. Army got interested and awarded GE a contract for building the experimental vehicle.
But the machine was too hard to control and the project was scrapped. However, Kevin Weir at flux machine recently reanimated the Walking Truck so the mechanical beast could gallop once more.
You can find out more about the Walking Truck and other machines like it here.