This sleek robotic dog may still be a mystery, but it clearly knows far more tricks than fetch, roll over and sit. Waltham-based Boston Dynamics has the tech world buzzing over a 24-second teaser video featuring its stylish new dog-like robot, SpotMini, which can climb stairs, handle objects and operate outdoors or in an office. The not-quite two-and-a-half foot tall, 60-pound robot is the smaller, younger brother of the company's Spot model, which was also unveiled with a YouTube video in February 2015. The SpotMini is battery powered and has a state-of-the-art 3D vision system. "SpotMini is a small four-legged robot that comfortably fits in an office or home," the company wrote on its website. The teaser video posted online has been viewed more than 2.5 million times.