The Flash episode features the Rainbow Raider, or some version of him.
No, we're not kidding.
The actor named for the part in the official write-up is Patrick Sabongui, who plays Captain David Singh in the series. We've reached out to The CW for a clarification, since it seems unlikely that they would cast him as a Rogue or turn the character evil without mentioning it in the text. It's more likely that there was an error in the text.
In the comics, Roy G. Bivolo is a Batman, Booster Gold and The Flash villain known as the Rainbow Raider. He's able to remove color from objects, up to and including blinding heroes who oppose him by removing their eyes' ability to process color. Here, he seems to have a power set more appropriate to the DC villain Psycho-Pirate, manipulating people's emotions.
Check out the official write-ups below.
"Flash vs. Arrow" — (8:00-9:00 p.m. ET) (TV-PG, V) (HDTV)
PART ONE OF THE EPIC CROSSOVER EVENT WITH THE FLASH AND ARROW — Barry (Grant Gustin) is thrilled when Oliver (guest star Stephen Amell), Felicity (guest star Emily Bett Rickards) and Diggle (guest star David Ramsey) come to Central City to investigate a case involving a deadly boomerang. Excited about teaming up with his friend, Barry asks Oliver if he'd like to help him stop Ray Bivolo, the meta-human Barry is currently tracking. Bivolo causes people to lose control of their emotions and has been using that skill to rob banks. Unfortunately, the superhero partnership doesn't go as smoothly as Barry expected. When Oliver tells Barry he still has a lot to learn, Barry sets out to prove him wrong by attempting to stop Bivolo alone. However, when Bivolo infects Barry and sets him on a rage rampage, everyone is in danger, and the only one who can stop him is the Arrow. Meanwhile, Iris (Candice Patton) is furious when Eddie (Rick Cosnett) tries to get a task force to stop The Flash, Joe and Dr. Wells (Tom Cavanagh) agree the Arrow is a bad influence on Barry, and Caitlin and Cisco deal with a new team in S.T.A.R. Labs. Glen Winter directed the episode with story by Greg Berlanti & Andrew Kreisberg and teleplay by Ben Sokolowski & Brooke Eikmeier (#107). Original airdate 12/2/2014.
"The Brave and the Bold" — (8:00-9:00 p.m. ET) (TV-14, LV) (HDTV)
PART TWO OF THE ARROW AND FLASH CROSSOVER EVENT — Oliver (Stephen Amell), Arsenal (Colton Haynes) and Diggle (David Ramsey) track down the location of a boomerang-wielding killer named Digger Harkness (guest star) but are surprised when they come face to face with an A.R.G.U.S. team. Diggle asks Lyla (guest star) why A.R.G.U.S. is involved but she defers until Harkness attacks the building, killing several agents and targeting Lyla. The Arrow joins the fight and gets help from an old friend – The Flash (guest star Grant Gustin). Harkness manages to get away and Oliver teams up with Barry again to find him before he can get to Lyla. When Harkness plants five bombs in the city that are timed to explode at the same time, both teams must come together to save the city. Jesse Warn directed the episode with story by Greg Berlanti & Andrew Kreisberg, and teleplay by Marc Guggenheim & Grainne Godfree Schwartz (#308). Original airdate 12/3/2014.