The Weighted Storage Cube is not a character in the traditional sense, but it is a recurring 'companion' and essential puzzle element. These cubes are used to activate large red buttons, hold down pressure plates, or block laser grids. They can be picked up, dropped, and transported through portals. There are different types of cubes, including the standard Weighted Storage Cube and the Weighted Companion Cube. The Companion Cube, introduced later in the game, is identical in function but has hearts on its sides and is given a distinct personality by GLaDOS, leading to one of the game's most memorable moments. Mastering the manipulation of these cubes with portals is fundamental to solving many puzzles.
