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. Please be careful."

- GLaDOS

The Combine Energy Ball, also known as Energy Orb, is a concentrated sphere of Dark Energy plasma, a form of exotic matter that disrupts spacetime and distorts light.

Overview
Energy Balls are generated by Combine Dark Energy reactor systems and transmitted through the plasma conduits of Citadel power transfer systems. Energy Balls can be contained within specialized dark energy cores, portable long-term storage devices that can later be used in Combine dark energy devices. As well as power generators, dark energy cores can be used by the Pulse Rifle, which can store the energy until released by the rifle's secondary fire.

Energy Balls repel themselves from matter of sufficient mass and density, bouncing off walls, ceilings and floors without losing inertia. However, when they strike matter of low density or mass, they are destroyed, causing them to dissolve into nothing. Gordon's HEV Suit, being plated, may explain why the player will sometimes deflect the orb rather than absorb it upon impact.

Energy Balls are subject to zero-point energy fields, allowing them to be grabbed and manipulated by the Gravity Gun.

OSIPR-fired Energy Balls can be deflected by a blast made with the Gravity Gun. After it becomes supercharged in the Citadel, the Gravity Gun is also able to grab them, until the effect wears off. Doing this will earn the "Think Fast!" achievement in the Xbox 360 version of The Orange Box.

The Energy Ball is used towards the end of Half-Life 2 to disable Combine Force Fields and ground turrets in the Overwatch Nexus.

The player is required to use the Gravity Gun to force the orbs from Combine Power Generators and thus disable the connected components.

Behind the scenes
In Portal, the "Aperture Science High Energy Pellet" bears a remarkable resemblance to the Energy Ball. However it is unknown if the two have any relation.

List of appearances

 * ''Half-Life 2
 * Half-Life 2: Deathmatch
 * Half-Life 2: Lost Coast
 * Half-Life 2: Episode One
 * Source Particle Benchmark
 * Portal
 * Half-Life 2: Episode Two