Stargirl (Sarah Grey) has officially arrived on "DC's Legends of Tomorrow." A new teaser for the show's sophomore season reveals a blink-and-you'll-miss-it look at the new character, who will join the team this fall. The trailer also offers a glimpse of Legion of Doom member Reverse Flash (Matt Letscher), who will also appear in "The Flash" Season 3.

Courtney Whitmore, also known as Stargirl, was created by Geoff Johns and Lee Moder and debuted in 1999’s “Stars and S.T.R.I.P.E.” # 0. She wields a cosmic staff that allows her to manipulate energy and fly. Stargirl made her live-action debut later seasons of “Smallville” where she was played by Britt Irvin. Grey joins Patrick J. Adams (Hourman), Maisie Richardson-Sellers (Vixen) and Matthew MacCaull (Commander Steel) as a member of the JSA.

Letscher's Reverse Flash also makes a brief appearance. This season, he'll join Malcolm Merlyn (John Barrowman), Damien Darhk (Neal McDonough), and -- yes -- Captain Cold (Wentworth Miller). Together, they will form the Legion of Doom. The roots of the Legion of Doom lie in the 1978-1979 season of the animated “Super Friends,” called “Challenge of the Super Friends,” which introduced a team of supervillains led by Lex Luthor. Other members included Captain Cold, Brainiac, Gorilla Grodd, The Riddler, Cheetah and Bizarro.

Starring Brandon Routh, Caity Lotz, Arthur Darvill and more, “Legends of Tomorrow” returns to The CW for its second season on Thursday, October 13, at 8 p.m. ET/PT.