A member of an advanced civilization located in the star system 61 Cygni, Ffa'rzz could only watch as his race was struck by a terrible plague of unknown origin. Within a week all were dead, save him. The shock apparently unhinged Ffa'rzz who then left his homeworld "to sow discord and disharmony among the galaxies...to prove that life is brutal, pointless and stupid!"
For nearly twelve thousand years Ffa'rzz, now known as the Mocker, traveled until his starship's energy source was nearly depleted. Seeking to spread chaos, he used the remainder of his energy to reach Oa. There he would disrupt the orderly works of the Guardians of the Universe and their Green Lantern Corps. To this end, he gained mental control of the Guardians and various Green Lanterns.
A lone Green Lantern, Katma Tui of Korugar, escaped Ffa'rzz' evil influence but was left drained by his attempts at subjugation. She escaped her mind controlled peers to warn Green Lantern of Earth Hal Jordan of the threat the Corps faced.
Jordan, accompanied by his alien friend Itty, traveled to Oa where he was attacked by the Guardians and the Corps. The spell was broken when Jordan blocked the emerald beams of his fellow Lanterns with the form of a Guardian. Inexplicably, the immortal Guardian died. The Corps were to discover Oa had been invaded by a hostile alien race. The invaders claimed there had been no barrier blocking them from attacking the planet, evidently another force had taken down Oa's protective shield.
Jordan recharged his power ring at the Central Power Battery on Oa, only to be threatened by an energy duplicate of his comrade Green Arrow. The Mocker revealed himself as the true threat to the Green Lanterns and the Guardians before he returned Jordan and Itty to Earth.
Now on Earth, the Mocker attacked Jordan, Green Arrow and the Black Canary before disappearing once more. Green Arrow correctly surmised the Mocker needed a power source close by from which to draw energy. Without a power source he would be formless. The heroes decided to leave Earth to prevent the Mocker from threatening anyone else on their homeworld.
Some time later, the two Green Lanterns, Green Arrow and Itty arrived at the monolithic spacecraft in the vicinity of Oa. Ffa'rzz the Mocker was waiting and launched an attack that was quickly repelled. Green Arrow theorized the Mocker had been inhabiting the body of Itty. Together, the heroes of Earth devised a plan to draw out the Mocker and finally trap him.
They made their way to the airlock of the starship and found a menagerie of alien objects and creatures. The Mocker captured the heroes and planned to leave them trapped forever in the cold of space but for the resourcefulness of his foes. The Green Lantern of Earth had substituted an energy duplicate for himself, a duplicate that the Mocker captured. Unaware of the deception until too late, the Mocker was trapped by the real Hal Jordan. It was Katma Tui that would take the Mocker to face the Guardians of the Universe for his crimes.
The Mocker would later escape, targeting the Guardians as his enemies. Linking himself to the Central Power Battery, he was able to take the energy of Katma Tui's power ring as she attempted to charge it.
Unwittingly, by linking himself to the battery, the Mocker had given Katma Tui a way to defeat him. She knew what he knew, his past was open to her through the link to the Central Power Battery. Ffa'rzz the Mocker saw no purpose in life, he believed it was useless to look for a reason for existence.
The Green Lantern of Korugar brought her own memories into play against the Mocker's thoughts. The Mocker weakened as she grew stronger. Realizing Katma Tui posed a threat to him, he turned his powers on her. Katma Tui focused on the sacrifices she had made to become a Green Lantern, the love of Imi Kahn she had denied to serve the Corps.
The Mocker fell, unable to accept what he had seen. The Guardians would take care of the Mocker and help him find his purpose in existence. He has not been seen since. His current activities remain untold.