QUICK, TO THE S.T.A.R. LABORATORIES, THERE ISN'T A MOMENT TO LOSE

With Smallville ending production after ten seasons on May 13, 2011 left a huge hole for DC Comics television show entertainment.  Thus started what is commonly known as the Arrowverse.  The television series about Green Arrow entitled Arrow broadcasted it's first episode on October 10, 2012.  The second volume of the Flash television series broadcasted it's first episode on October 7, 2014.  The television series Supergirl broadcasted it's first episode on October 26, 2015.  The television series Legends of Tomorrow broadcasted it's first episode on January 21, 2016.  And ever since the establishment of the Arrowverse, characters from one Arrowverse show has frequently appeared on another Arrowverse show creating an alternate reality replacing Smallville and establishing a brand new world all it's own with familiar characters. 
The following are scenes from the upcoming episode of the CW Network television series the Flash entitled Duet.  This is the first comic book super-hero television series episode to incorporate elements of toe tapping musical extravaganza genre into the super-hero genre.

Grant Gustin as Barry Allen aka the Flash and Melissa Benoist as Kara aka Supergirl (From the Supergirl television series)

 John Barrowman as Malcolm Merlyn aka Black Arrow (From the television series Arrow)

 Carlos Valdes as Cisco Ramon aka Vibe (From the television series the Flash)

 Grant Gustin as Barry Allen, Melissa Benoist as Kara, Carlos Valdes as Cisco Ramon, Darren Criss as Music Meister and John Barrowman as Malcolm Merlyn

 Darren Criss as Music Meister, Jeremy Jordan as Winn Schott aka the Toyman Jr.  (From the television series Supergirl) and Carlos Valdes as Cisco Ramon

 Melissa Benoist as Kara and Grant Gustin as Barry Allen

 Melissa Benoist as Kara, Grant Gustin as Barry Allen and Darren Criss as Music Meister

 Grant Gustin as Barry Allen and Melissa Benoist as Kara

 Victor Garber as Professor Martin Stein aka Firestorm---The Nuclear Man (From the television series Legends of Tomorrow), Jesse L. Martin as Detective Joe West (From the television series the Flash), Grant Gustin as Barry Allen and Melissa Benoist as Kara

 Grant Gustin as Barry Allen

  Jesse L. Martin as Detective Joe West

 Melissa Benoist as Kara

 Grant Gustin as Barry Allen, Candice Patton as Iris West (From the television series the Flash), Jesse L. Martin as Detective Joe West (Iris West's father) and Victor Garber as Professor Martin Stein

 Grant Gustin as Barry Allen

 Grant Gustin as Barry Allen, Jesse L. Martin as Detective Joe West, Candice Patton as Iris West and Victor Garber as Professor Martin Stein

 Victor Garber as Professor Martin Stein and Jesse L. Martin as Detective Joe West

 Candice Patton as Iris West, Victor Garber as Professor Martin Stein and Jesse L. Martin as Detective Joe West

The Volume One and Issue #64 of Action Comics which introduced Winslow Schott aka the Toyman for the first time ever on September 1943.

The Volume One and Issue #1 of Firestorm, the Nuclear Man which introduced the character for the first time ever on March 1978.

 The Volume One and Issue #3 of Firestorm, the Nuclear Man which introduced Killer Frost (Who at the time had the name Dr. Crystal Frost as her secret identity) for the first time ever on June 1978.

Justice League of America Annual #2 which introduced  Paco Ramone or Francisco "Cisco" Ramon aka Vibe for the first time ever on October 1984.

 Chris Wood as Mike aka Mon-El aka Lar Gand aka Valor (From the television series Supergirl), Melissa Benoist as Kara/Supergirl and David Harewood as Hank Henshaw aka J'onn J'onzz aka the Martian Manhunter (From the television series Supergirl) mocking the cover (Or paying tribute to the cover) for Issue #7 for the twelve issue comic book mini-series Crisis on Infinite Earths.  Both Supergirl and the Flash were among the numerous fatalities at the hands of the Anti-Monitor--The main villain of the comic book mini-series Crisis on Infinite Earths.

Unrelated observation:  J'onn J'onzz aka Martion Manhunter using the name Hank Henshaw is confusing because Hank Henshaw is the secret identity for a genocidal maniac named the Cyborg Superman (Who has the same super-powered abilities as Clark Kent aka Superman (Who never shows up in the Arrowverse), but there are cyborg abilities also involved).  Comic book Hank Henshaw aka Cyborg Superman and comic book J'onn J'onzz aka Martian Manhunter are not the same person---Not even to the vaguest level.

 

 Carlos Valdes as Cisco Ramon, Grant Gustin as Barry Allen, Candice Patton as Iris West, Tom Cavanagh as Harrison Wells (From the television series the Flash), Chris Wood as Mike, Melissa Benoist as Kara/Supergirl, Danielle Panabaker as Dr. Caitlin Snow aka Killer Frost (From the television series the Flash), and David Harewood as Hank Henshaw

 Carlos Valdes as Cisco Ramon and Chris Wood as Mike

 David Harewood as Hank Henshaw, Candice Patton as Iris West, Grant Gustin as Barry Allen, Melissa Benoist as Kara, Chris Wood as Mike and Carlos Valdes as Cisco Ramon

Carlos Valdes as Cisco Ramon, Tom Cavanagh as Harrison Wells, Grant Gustin as Barry Allen aka the Flash and Keiynan Lonsdale as Wally West (Iris West's brother.  He also uses the super-hero identity of the Flash (From the televisions series the Flash))

Here is proof that the comic book version of Hank Henshaw isn't the secret identity of J'onn J'onzz aka Martion Manhunter, but rather is the secret identity of a genocidal maniac super-villain named the Cyborg Superman.  I know it's confusing because the Cyborg Superman once lead an army of evil Robot Manhunter Drones which has nothing to do with the Martian Manhunter, but Hank Henshaw aka the Cyborg Superman isn't a Manhunter himself.

 This has nothing to do with anything that you have seen above.  I just thought you would find this interesting.  President Bill Clinton orders Clark Kent aka Superman to save the Earth in cooperation with the United States Armed Forces.