A trackball, as rotated to control a cursor on a computer. An alternative or supplement to a computer mouse or touchpad. Generally depicted as a cordless device with a blue or red ball in a cylindrical, black or gray socket.
Occasionally used for various content concerning gaming. Google’s design features a cord, Facebook’s a rectangular base.
Trackball was approved as part of Unicode 7.0 in 2014 and added to Emoji 1.0 in 2015.