https://www.cnet.com/news/someone-built-a-computer-inside-a-mouse-and-its-super-cute/

Don't expect to be blown away by its specs. The mouseputer has a 1GHz, single-core CPU with 512MB of RAM. (The chip in your smartphone can probably run circles around this thing.) It has a 1.5-inch OLED screen with 128x128 RGB pixels and it's powered by a 500-mAh battery.

Still, the device works and can even play Minecraft -- although Electronic Grenade admits the software crashed after a bit.