Just days after the Justice League battled their first-ever foe on the big screen, The Flash brought back Wally West, who revealed he had taken on the League's first comic book foe during his time in Blue Valley.
After an unexpected return from his self-seeking sabbatical, Barry asked Wally if he had found what he was looking for.
"Self-reflection and a battle with a starfish from outer space gives you perspective," Wally told Barry.
That is a reference to Starro the Conqueror, an alien being of immense power.
Starro the Conqueror is a member of the Hatorei species who used their innate psychic abilities to gain control of a Star Conqueror Motherstar in the distant past and who uses the Starros as his instrument of conquest. He has faced the Justice League over and over again, and in the 31st Century even took over a large chunk of the universe and became a recognized power.
Starro, who in a simpler time would have likely been considered unfilmable, appeared in a brief cameo on last year's DC sitcom Powerless, in which he was killed by Green Lantern and splattered all over the window of Emily Locke (Vanessa Hudgens).
Starro first appeared in The Brave and the Bold #28, in which he recruited a trio of earth's starfish to his cause, loaned them a fraction of his power, and did battle with the Justice League in their first appearance.
The Flash airs on Tuesday nights at 8 p.m. ET/PT on The CW.