The Flash: 10 Best Characters Who Only Appeared In One Episode
8. Trajectory
The idea of artificially powered speedsters is intriguing, and offers a nice contrast to the more naturally gifted likes of Barry Allen and Eobard Thawne. This is explored with the introduction of Eliza Harmon/Trajectory, a newly empowered speedster who unfortunately let her incredible power corrupt her.
Once a scientist at Mercury Labs, Harmon gained her abilities after experimenting with the Velocity 9 serum following a brief project with Caitlin Snow. The scientist was desperate to make progress with her own research, and this led to her taking the volatile drug.
Her use of Velocity 9 dramatically increased her speed but also affected her mental state and led to Trajectory committing a variety of crimes, with each crime increasing in intensity and scope. This series of events led to her clashing with the Flash and his allies, and she had Caitlin and Earth-2 Wells make her more Velocity 9.
Ultimately her thirst for power was her undoing, as she took a huge amount of the drug; an act that led to her disintegration and demise.