Dark matter is the most common form of matter in the universe. It is "dark" because it does not interact with the electromagnetic force. But it can be generated from normal matter through the weak nuclear force, and it can be detected by its gravitational influence on the shape of large visible structures such as galaxies and superclusters.
The abundance of dark matter is 23% of the total mass of the universe, which is far larger than the 3.6% of mass represented by non-visible normal matter, such as interstellar gas, and 0.4% of mass represented by visible stars. But 73% of the mass of the universe is bound up in the mass-equivalence of the energy of free-flying photinos, also known as dark energy. But the influence of this dark energy is repulsive, a form of anti-gravity. It causes the general expansion of the universe to accelerate.
Dark matter comes in three varieties based on its relative velocity.
Hot dark matter consists of neutrinos, generated by the conversion of a proton into a neutron, and antineutrinos, generated by the conversion of a neutron into a proton. These reactions were known in the Twentieth Century. Neutrinos have a very low rest mass, and travel at just under the speed of light. So infrequent are their interactions with normal matter that a neutrino would be able to pass through a light-year of lead with no scattering events.
Warm dark matter consists of negatinos, which have the supersymmetric equivalent of a negative charge and interact with photinos, which are gage bosons of dark energy. Negatinos travel at relative velocities between one to ten percent of the speed of light.
Cold dark matter consists of positinos which also can emit or absorb photinos and have a positive scharge. Cold dark matter typically has velocities from stationary up to one percent of the speed of light.
In 1838, during its last visit to Earth before the Industrial Revolution, the Other gave the Golden Gift to a brave named Malekwa, a member of a nameless clan of native Americans in the foothills of th eEnfilade Range near modern day River City. This gift was used as a weapon, and the brave soon became Chief. In the mid-21st Century a latter-day member of this clan, Robyn Shy Bear, analyzed the Golden Gift heirloom and discovered it converted protons to positinos and electrons to negatinos.
It is theorized that dark matter is the lowest entropy rest state of the "stuff" that makes up the universe. What we call normal matter is a tiny minority that exists out of equilibrium with the rest of reality, created and locked into its precarious position during the enormous violence of the earliest fractions of a second of the expansion of the universe in a mechanism similar to that which established the superabundance of matter over anti-matter.