Phazon

An important part of the Metroid Prime storyline is a highly mutagenic radioactive substance of unknown origin known as Phazon. Direct exposure to this electric blue-coloured substance results in either a violent death or the rapid addition of new abilities and/or organs. It seems to exist naturally as a solid and sometimes as a liquid, but its solid form may be considered more common---and possibly a metal---as many Space Pirate log entries call for mining of Phazon ore.

Phazon was spread throughout Tallon IV when a meteorite containing it crashed into the planet’s surface. The Phazon immediately began negatively influencing the indigenous flora and fauna – it either killed them or severely mutated them. A group of Chozo colonists tried to seal away the Phazon source with a mystic seal called the Cipher, which was an enormous temple linked to twelve artifacts, which they then spread across the planet. Some Chozo lore texts suggest that Chozo who were exposed to Phazon became violent and destructive wraiths. A long time after the Chozo contained the source of the Phazon, the Space Pirates picked up on an unknown and powerful energy signature. After their first defeat on Zebes at the hands of bounty hunter Samus Aran, they were eager to find a powerful energy source to rebuild their army, and so tracked the energy signature back to Tallon IV. The Space Pirates tried to use the substance, now dubbed Phazon, to mutate various species for use as biological weapons, including some of their own people and even some native materials. Scans of Space Pirate computer terminals verified a high death rate in many subjects, especially when the descendants of the original Phazon-exposed creatures were exposed to the substance.

In the North American version of the game, the Space Pirates also discovered a powerful creature that produced Phazon. They named it Metroid Prime. While Metroid Prime exists in the European version of the game, the Space Pirates never actually discovered it.