It amuses shoppers of all ages, but last Thursday, 16-month-old Harwin Cheng had a frightening collision with the robot. "The robot hit my son's head and he fell down facing down on the floor and the robot did not stop and it kept moving forward," Harwin's mom Tiffany Teng said. Harwin's parents say the robot ran over his right foot, causing it to swell, but luckily the child didn't suffer any broken bones. Harwin also got a scrape on his leg from the incident. "He was crying like crazy and he never cries. He seldom cries," Teng said. Stanford Shopping Center and Knightscope, the Mountain View company that built the robot, have yet to respond to our emails and voicemail messages.