Anti-matter

Antimatter consist of particles that share the same mass as their matter counterparts, but qualities such as electric charge and other quantum numbers (such as spin) are opposite. The positively charged positron, for example, is the antiparticle to the negatively charged electron.

Contact between matter and antimatter results in annihilation, with tremendous amounts of energy produced, according to the famous equation e=mc^2.

In works of fiction, anti-matter is usually depicted as a source of energy, or as a destructive force that can consume and annihilate normal matter when both make contact with each other. In DC Comics' Crisis On Infinite Earths, a wall of anti-matter energy consumes all but five of the positive-matter universes in the Multiverse.

Left Behind: Global Justice
In the Left Behind: Global Justice universe, a scientist friend of Chaim Rosenzweig who becomes a Christian during the Tribulation postulates the idea that the "fire of God" that will destroy the heavens and the earth at the end of time may be anti-matter or entropy that will consume everything. In the series' distant finale, a wall of fire does devour everything, but causes mankind, both the living and the dead, to pass through safely in order to face the Great White Throne judgment.

Autumnrose2010
In the stories Mercy and Kingdom Come: Extended Ending, antimatter is used to propel the Second Ark away from the Earth immediately after the Last Battle.