Life is a force that appears in the Sonic the Hedgehog series. Although it is never explained what exactly this energy is, it appears to the very force of life itself.
Life takes the form of a green liquid that can be ingested by organic beings and robots alike. It can likewise be used as fuel for machines. This energy is highly powerful, and is capable of empowering both machines and organic beings. The more one ingest, the more powerful they become.
Life seems appropriately to be infused in all living things on Sonic's world. When life is removed from a target however, it will slowly lose its color, resulting in any organic life being rendered completely white. If too much life is removed however, the target will slowly wither away, and eventually die.
Sonic Lost World
In the Wii U version and PC version of Sonic Lost World, Dr. Eggman constructed a machine known as the Extractor which was able to suck out the Life of the Sonic's world itself and condense it into its familiar green liquid state. The machine, however, was made only to siphon off small, harmless amounts of energy from the planet. However, the Deadly Six eventually took over the control of the Extractor to extract all the life energy from the world, growing more powerful over time. After Sonic defeated the Deadly Six and Dr. Eggman, Tails managed to reprogram the Extractor to return the stolen energy back into the planet, restoring natural life.
- The world's life can be compared to the Lifestream from Final Fantasy VII, in which it is the essence of the life of Gaia itself which can be extracted in a green liquid energy state known as Mako energy.