The High Energy Pellet is first introduced in Test Chamber 06 and is present in most of the following Test Chambers. In Test Chamber 17, Chell must use two corridors where Energy Pellets come and go. This is where the Weighted Companion Cube is introduced to protect her against the balls. An energy ball that kills Test Subjects in a single hit and thus must be avoided at all costs, it is used in Test Chambers to allow Test Subjects to proceed further, by opening doors or raising Unstationary Scaffolds. To do so, the ball is launched by its launcher and must reach its catcher. Most of the time Test Subjects have to direct it through a portal so that it reaches the catcher. Once placed, the catcher closes, holding the ball inside, the ball launcher stops creating energy balls, and the linked object(s) opens and/or activates. High Energy Pellets tend to disintegrate after a few seconds, after which a new one is deployed. It also includes a green variant that never disintegrates. It is seen in Test Chamber 19. It can also be used against Sentry Guns. However it just pushes them and does not destroy them.