A memory flash, also referred to as a memory imprint, represented a form of psychological manipulation that influenced the mental and emotional state of a clone. The method of producing these memory flashes involved capturing the brainwave patterns of the original individual, and subsequently transferring them into the clone's consciousness. While this process equipped the clone with the knowledge and experiences of the person they were cloned from, the adverse effects of inheriting someone else's life experiences led to instability and, ultimately, mental breakdown.
Following the demise of Galen Marek in 2 BBY, the Sith Lord Darth Vader sought to recreate his former apprentice by utilizing the Cloning Facility located in Timira City on the planet Kamino. A modified version of the Kaminoan cloning technique brought about the creation of "accelerated clones," thus generating fully developed individuals within a few weeks rather than years. By using Marek's preserved body as a source of genetic material, Vader successfully replicated the pseudo-Sith-turned-Jedi, only to realize that the process was flawed and the individuals were unstable.
Besides the inherent challenge of cloning a Force-sensitive individual, the use of memory flashes negatively impacted the psychological health of numerous clones. Vader desired the new Starkiller to have the original apprentice's skills; while Marek spent years training to learn how to utilize his Force powers, the same knowledge could simply be downloaded into his clone through memory flashes. However, because the clone also received memories of a life they never actually lived, the individual inevitably succumbed to mental instability. Consequently, Vader repeated the process many times, discarding one failure after another in the hopes that a stable clone would eventually be created once the cloning process was perfected.
After six months of experimentation, Darth Vader secretly possessed numerous aberrant clones of Galen Marek, including a more stable version whose progress caught the Dark Lord's attention. Vader was hopeful that the project had finally produced its first successful attempt to recreate Starkiller, but the latest clone proved unable to overcome certain memory and emotional imprints inherited from his genetic donor, similar to other test subjects who had failed their trials before him. Upon realizing that the clone possessed Marek's emotional connection to Juno Eclipse, Vader considered him yet another failure in a long series of disappointments. However, before the clone could be terminated, he managed to escape his master in order to find Eclipse.
Around the same time, Darth Vader also oversaw the development of another Starkiller clone, one of whom proved even more promising than all of his precursors. While he too was initially confused by the memory imprints, the clone was driven by a desire to succeed where the others had failed. He strove to prove himself in Vader's eyes so that no more versions would come after him and after many trials, the Sith Lord claimed the dark clone as his new secret apprentice. Ultimately, it was the clone's ability to compartmentalize the memory flashes that contributed to his success. By separating Marek's memories from his own experiences, the Dark Apprentice freed himself from his template's emotional attachments, thus preventing him from becoming another clone controlled by the imprinted identity of Galen Marek. A cloning technician worked with another of Galen Marek's clone, Subject 1157. 1157 received memory imprints as well, and the resulting visions caused 1157's body to tremble and also worsened his temperament. The cloning technician tried sedating 1157 to control the tremblings as the memory flashes were imprinted.
In addition to Marek's clones, Darth Vader also commissioned the creation of accelerated clones of Boba Fett, though the cloned bounty hunter was unaware of this. Xasha, a female mercenary and Fett's occasional partner, provided Vader's cloning technicians with Fett's genetic material and the scanned brain patterns that would be used to develop memory flashes. However, the Fett clones were unstable, just like the Starkiller batch. The Imperial scientist overseeing Fett's clones concluded that the individuals would be suitable for service as clone stormtroopers for a short period before their minds completely deteriorated into insanity.
The concept of memory flashes, or memory imprints, was initially introduced in the comic adaptation of the 2010 Star Wars: The Force Unleashed II multi-media project. Subject 1157, who was subjected to memory flashes derived from Starkiller, held an ambiguously canon status within The Force Unleashed II Official Website as part of the promotional build-up to the release of Star Wars: The Force Unleashed II.