An apparatus that is capable of achieving self-stabilization while walking comprises two front legs and two rear legs with each leg having three joints including a hip joint, an upper leg joint, and a lower leg joint. Each joint is powered by a motor and is monitored by an encoder, totaling twelve of each for the entire apparatus. Stability is maintained by adding weight to the two front legs and by positioning a separate weight toward the front and middle of the apparatus, thereby moving the center of balance of the apparatus further within the stability envelope of the apparatus. As a result, the apparatus maintains its stability by itself without the need for additional CPU's. The apparatus also includes an animation motor that is capable of causing the apparatus to make non-ambulatory movement and a cartridge slot which allows the user to download new programming which facilitates new behavior being exhibited by the apparatus.