Dark Matter (Earth-1: Pre-Crisis)

Dark Matter are particles that are able to mutate Humans into Metahumans.

Ancient Times
In the ancient times, a Black Diamond was created with Dark Matter.

First Particle Accelerator Explosion
On December 11, 2013, the S.T.A.R. Labs Particle Accelerator exploded and released a high amount of Dark Matter to the city which mutated 2600 people into Metahumans.

Second Particle Accelerator Explosion
In a trial to allow Barry Allen regain his superhuman speed, they created another explosion which created excessive Dark Matter in the building and put Jesse Wells in a coma which was healed by Dark Matter from the Sped Force.

Thinking Cap
In 2018, Harry built the Thinking Cap to defeat Clifford DeVoe. However, he thinks it should improve and he infused it with excessive Dark Matter which caused him to slowly lost his intelligence.