Referring to Vigilante, Barry says to Oliver, "Ollie, It looked like he was about to Scarface (1983) you guys."
Cisco says, "Barry and Oliver stayed behind when everyone went to save the President but now everyone's crazy and goin' all Kill Bill on the both of them."
Oliver Queen is recruited to help fight the Dominators in part one of a three-part episode that continues on Arrow: Invasion! (2016).
Referring to the Dominators, Barry says, "These things look like World War Z (2013) zombies."
mentions of Oliver once shooting Barry
Supergirl is brought from another universe as seen in Supergirl: Medusa (2016).
The Legends are recruited to help fight the Dominators in part one of a three-part episode that concludes on DC's Legends of Tomorrow: Invasion! (2016).
Barry Allen and Cisco Ramon come from another universe as seen in The Flash: Invasion! (2016).
Barry and Cisco recruit Kara to help fight the Dominators.
"Invasion!" is #1.