In 2011, I spent 4.5 months in China, most of them in Shanghai. During that time, I also spent some time at the Shanghai hackerspace, XinCheJian. We were invited to take part in the Seeed Studio Toy Hacking Contest, and I decided to modify a Maneki Neko, also known as the beckoning cat. Most of them have a mechanism in them, which lets one of their arms (usually the left one) move back and forth endlessly. But what would people do it all the sudden, it would start waving its arm sideways?
Using a freshly bought cat toy, some servos and electronics from the kit provided as part of the contest, and some metal parts found around the hackerspace, the cat was modified to move its arm sideways every once in a while, and pretending to be totally normal the rest of the time.
The documentation for the project can still be found here, and there’s also a GitHub repository containing said documentation as well as the Arduino code to control the two servos.
Years later, I also wrote an Instructable covering the same project.