Abra Kadabra and Flash in “Unfinished Business”

After our last run-in, I returned to the future to figure out why I failed to defeat an unevolved primitive such as yourself. Do you know what I discovered?

That you're a terrible villain?

Temporal paradoxes! You're a part of my history, therefore I can not defeat you without changing the timeline. But in my research I found something that may be of interest to you. (materializes newspaper) Notice the date? It's today. I may not be able to kill you, but I can watch someone else succeed what I have failed. The article mentions a Mirror Master...