Cats are amazing creatures to adopt and take care of. You need to keep them busy though. The Mousr Robotic Mouse could be just what you need. Unlike many other toys on the market, this robot offers automatic reactive play. You can also control it from your smartphone. Mousr has 360 degree vision, Bluetooth connectivity, and an IMU to stay on track. It will have multicolor eyes, interchangeable tails, and a hidden speaker.
You can get a Mousr robotic mouse for as low as $100 on Kickstarter (if you are early).