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This article is within the scope of the Portal Project, a collaborative effort to improve articles related to Portal and Portal 2. See the project page for more details about the article status.
This article is about the Aperture Science energy ball. For the Combine ball, see Energy Ball.
"While safety is one of many Enrichment Center goals, the Aperture Science High Energy Pellet, seen to the left of the chamber, can and has caused permanent disabilities such as vaporization."

The Aperture Science High Energy Pellet is a testing element used in the Test Chambers of the Aperture Science computer-aided Enrichment Center. It is only seen in Portal and is replaced with the Thermal Discouragment Beam in Portal 2.



The first High Energy Pellet in Test Chamber 06.

  • The High Energy Pellet kills The Player 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, raising or lowering platforms, or activating Unstationary Scaffolds. To do so, the pellet is thrown by it's emitter 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 greener variant that never disintegrates. It is seen in Test Chamber 19.
  • 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.
  • It can also be used against Sentry Turrets. However, it only pushes them and does not directly destroy them.
  • The Pellet appears to recharge when going through portals, which will lengthen its life.
  • Objects like a Weighed Storage cube or Cameras could be used to redirect High Energy Pellets.

Behind the scenes

Video game-wise, the High Energy Pellet is identical in all aspects to the Combine Energy Ball; it has the same appearance and the same sound effects. The only difference is that it instantly kills the player. Whether they are related storyline-wise or whether the High Energy Pellet is made of the same Dark Energy used by the Combine is unknown. Of note is that unlike the Combine Ball with the Gravity Gun, it is not affected by the Portal Gun's zero-point energy field because it is equipped with a weaker field. Using the console to obtain the Gravity Gun and picking it up will result in the energy ball having the same behavior as the Combine Energy Ball. It is also possible to use the Pulse Rifle's secondary fire as a substitute on the catcher without using portals.


  • Although the Pellet itself is not used in Portal 2, the launcher makes three appearances, and the catcher appears too. In GLaDOS' Test Chamber 01, the launcher and catcher are seen being replaced with Thermal Discouragement Beam emitter and catcher respectively. In ruined Test Chamber 07, the launcher's workings can be seen, however, the launcher to be yellow cone-shaped device much larger than the actual launcher on the workings. In the ruins of Test Chamber 19, the Pellet Launcher can be seen but the receiver cannot.
  • If the spawn code is used for this prop in Portal 2, an untextured cube will appear.
  • This is one of the few testing elements that mostly requires timing.


List of appearances


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