It's Mr. Pants (originally Donkey Kong Coconut Crackers) is a video game for the Game Boy Advance. The starring character, Mr. Pants, is the result of a poorly drawn image from Rare's website, who was used as a mascot for the site survey.
The basic idea of the game is to create rectangles which have to be 2x3 blocks or larger to clear them from the grid. Blocks cannot be placed on top of blocks of the same color that are already on the grid, but they can be placed on top of blocks of any other color which causes the different blocks on the grid to disappear.
The game incorporates three main game modes: Puzzle, Wipeout and Marathon. There is also a fourth game mode called "Max's Mystical Muddle" which is opened up by completing all of the puzzles in Puzzle mode.
Source: Wikipedia, "It's Mr. Pants", available under the CC-BY-SA License.