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This subject is from the Portal era.This subject is from the Portal 2 era.This is a safe article.
Imagecat 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.


Aperture poster003a2

A High Energy Pellet on an Aperture Science propaganda poster.

The High Energy Pellet kills the Test Subject 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 its emitter and must reach its receiver. Most of the time Test Subjects have to direct it through a Portal so that it reaches the receiver. Once placed, the receiver closes, holding the Pellet inside, the emitter stops emitting Pellets, and the linked object activates.

High Energy Pellets disintegrate after a few seconds, after which a new one is emitted, although it appears to recharge when going through Portals, which will lengthen its life. A green variant, that never disintegrates, is seen in Test Chamber 19.

Objects like Weighted Storage Cubes, Security Cameras or Sentry Turrets can be used to redirect High Energy Pellets.

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 cross two corridors where Energy Pellets come and go, this is where the Weighted Companion Cube is introduced to protect her against the Pellets.

Behind the scenes

Gameplay-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 story-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. Using the console to obtain the Gravity Gun and picking it up will result in the High Energy Pellet 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 receiver without using portals.


Portal 2 PotatoFoolsDay ARG Ruined Aperture Laboratories Concept Art 6

Portal 2 concept art.

  • Although the Pellet itself is not used in Portal 2 the emitter and receiver make appearances.
    • In the ruins of Test Chamber 07, the emitter and receiver can be seen at the same time.
    • In the ruins of Test Chamber 19, the Pellet emitter can be seen in the idle_open position, but the receiver cannot.
    • In GLaDOS' Test Chamber 01, the emitter and receiver are seen being replaced with Thermal Discouragement Beam emitter and receiver respectively.
  • If the spawn code is used for this entity in Portal 2, an untextured cube will appear.
  • This is one of the few testing elements that mostly requires timing.




List of appearances


  1. Scott Klintworth's official website