The Flash season 6 premiere, "Into The Void," finally made use of what many would think would be the perfect theme song for Barry Allen - Queen's "Flash's Theme." Granting that the song was written for the 1980 Flash Gordon movie, it still seems to be a fitting anthem for the Fastest Man Alive and it certainly fit the action of the episode.
The plot of "Into The Void" centered around a mysterious black hole, which began manifesting around Central City. Team Flash eventually tied the black hole to Chester P. Runk; a science-geek with a streaming show, who built amazing technology out of spare parts he retrieved from a junkyard. In his final video before being left in a comatose state, Runk had apparently created a controllable black hole in his laboratory. The team determined that Runk's conscious mind had somehow become bonded to the black hole and that his efforts to bring body and soul back together were causing the void to manifest in locations that were personally important to Runk. Armed with this knowledge, Team Flash was able to formulate a plan that would let them save Runk and Central City.
The plan involved using an advanced electrical filament sewn into The Flash's costume to contain Runk's synaptic energy before reuniting it with his body. Unfortunately, this required The Flash enter into a black hole and outrun the gravitational pull of its core long enough to retrieve Runk's mind and escape. This is physically impossible, as the mass of a black hole is near-infinite and an object would have to travel faster than light to escape it. Thankfully, the Speed Force allows Barry Allen to do many things that are physically impossible and surviving the inside of a black hole can now be added to that list. As Barry began to build up the speed needed to rush the event horizon, Cisco Ramon (who was monitoring the situation from STAR Labs) declared that he had been "saving this for the right moment since day one." With one keystroke, John Deacon's familiar bass line was broadcast around STAR Labs, as Freddie Mercury proclaimed that Flash was "savior of the universe" and "a miracle."
Iris West-Allen rolled her eyes at this blatant act of geekiness, but Cisco defended himself, pointing out that it had never been more appropriate to play "Flash's Theme" by Queen than during a moment in which The Flash was journeying into a vortex to save the world. Apart from adding the perfect background to an epic action scene, the song may also foreshadow the ending of "Crisis on Infinite Earths".
"Into The Void" ended with an appearance by the Monitor, who confirmed that the date of Barry's foretold disappearance had been pushed up and that he is fated to die in the coming battle. Regrettably, it seems that to save "every man, every woman, every child," in the multiverse, The Flash will have to make the ultimate sacrifice. Yet if anyone can find a way to defy fate, it is the Arrowverse's own "King of the Impossible," Barry Allen.