The Mini Rubik's Cube (aka the Pocket Cube) is a simpler version of the original Rubik's Cube. Instead of having 3x3x3 blocks it only has 2x2x2. Solving this puzzle is equivilant to solving only the corners of the Rubik's Cube.
This puzzle was actually invented 4 years before the Rubik's cube, in 1970, by Larry D. Nichols. He called it the "Twist cube" and used magents for its mechanism. The Rubik's brand patented their own design for this puzzle in 1983.
Derived from it's smaller size, the number of possible permutations is relatively low: 3,674,160. The current world record for solving the Mini Cube is 0.49 seconds. It was set by Maciej Czapiewski at the Grudziądz Open 2016.