We present the MIT Super Mini Cheetah, a small (sub-10kg) and low-cost (sub-10k$) quadrupedal robot for dynamic locomotion. The robot can control vertical and horizontal force and impedance at each foot and performs dynamically stable walking, jumping, pronking, turning and braking using simple force and impedance trajectories. We present design specifications for dynamic legs which were used to guide the selection of leg components (e.g., motor, gearbox, and limb geometry). We demonstrate experimental evidence of accurate force control during foot-ground impact and present video of locomotion gaits performed by the robot. To the best of our knowledge, this is the first small (sub-10kg), power autonomous quadrupedal robot to perform such a wide range of ballistic locomotion behaviors and demonstrate foot force control during impact.