Unstable Substances
Protomatter is a key component of the Genesis Device prototype—an experimental terraformation device introduced in Star Trek II: The Wrath of Khan. Protomatter is presented as a very unstable substance that, due to its instability, is considered unethical for usage in scientific research. The substance is used as a plot device to compare David Marcus with his father, James T. Kirk, both of whom, in Lieutenant Saavik's words, "changed the rules"—David Marcus in using the forbidden protomatter, and James T. Kirk in "cheating" to win the Kobayashi Maru test. The inclusion of protomatter ultimately results in both the accelerated maturation of the regenerated Spock during his stay on the Genesis planet, and the planet's subsequent explosion into an asteroid belt.
In an episode of Deep Space Nine, Protomatter was used by a Dominion changling in a bomb in order to destroy the Bajorian sun, to cause a first strike against the forces of the Alpha Quadrant in the episode By Inferno's Light.
Protomatter is also mentioned in the Star Trek Voyager episode "Mortal Coil", where it is said, "Protomatter's one of the most sought-after commodities. The best energy source in the quadrant."
The Omega Molecule is a highly unstable molecule believed to be the most powerful substance known to exist. If not properly disposed of, it may destroy subspace and render warp travel impossible. In Star Trek: Voyager, during the episode The Omega Directive, Voyager encounters Omega particles and Captain Janeway must comply with the Omega Directive and destroy the particles. Later in the episode, they spontaneously stabilize for a brief moment before they are destroyed.
Red matter is a red liquid material introduced in Star Trek (the 2009 film) that is able to create a black hole when not properly contained. Spock attempts to use it to stop a massive, galaxy-threatening supernova, but the resulting black hole causes his own ship and a Romulan mining vessel to travel back in time. Later in the film, the antagonist Nero uses it to destroy the planet Vulcan. Shortly after, the future Spock's ship containing the red matter is used to destroy Nero's Romulan mining vessel.
Read more about this topic: List Of Star Trek Materials