The way this thing moves needs to be seen to be believed. Developed in 2005 by Boston Dynamics (recently bought by Google) as a carrying mule for the army, BigDog is a quadruped robot designed to tackle tough terrains alongside soldiers. It's balance and ability to climb is astounding, making it one of the most creepy-looking robots to date, sheerly due to the way it's legs look 'alive' as it strives for balance, even when being pushed and kicked in the field. (See video below). BigDog is 3ft long, 2.5ft tall and weighs 110kg, making this a heavy-duty piece of equipment, but allowing it to carry up to 150kg at 4mph, even uphill. Powered by a 15hp go-kart engine and installed with around 50 sensors, the robot senses it's position and speed, sending the information back to the central computer that decides how to execute the next manoeuvre. Recently added to BigDog by Boston Dynamics was an arm that could pick objects up and throw them, making it just a little bit scarier than it already was.