When Harry Met Harry...

"When Harry Met Harry..." is the sixth episode of the fourth season of The Flash, and the seventy-fifth episode overall. It aired on November 14, 2017.

Synopsis
When collectors of Native American artifacts are attacked by a meta named Mina Chayton who can bring inanimate objects to life, Barry turns to a surprising ally for help. Determined to crack the identity of The Thinker, Harry enlists Cisco’s help to summon the ultimate think tank: “The Council of Wells’,” a roundtable of the brightest Harrison Wells’ from various Earths.

Trivia

 * The title of the episode is a reference to the 1989 film When Harry Met Sally...
 * When Harry was talking to his doppelgängers, a doppelgänger of him interrupted and said, "It is I! Wells the Grey!", a reference to Gandalf from the Lord of the Rings.
 * Discussing his attributes in reference to his doppelgängers, Cisco tells Harry that sometimes "you're a wizard, Harry". This is a play on the line spoken by Rubeus Hagrid to Harry Potter in the 2001 film Harry Potter and the Philosopher's Stone, and the 1997 book Harry Potter and the Philosopher Stone and also a reference to the previous bullet-point.
 * When Barry tells Ralph to suit up, the latter mocks it as the opposite of a "rousing Braveheart speech", referencing the infamous speech given by William Wallace in the 1995 film Braveheart.
 * When the Tyrannosaurus rex bones shake Ralph about, he cries "for the love of Jeff Goldblum", referencing the actor in the Jurassic Park franchise.
 * When the Tyrannosaurus rex came to life in the museum, it references the movie Night In The Museum when the museum exhibits came to life overnight.
 * While in S.T.A.R. Labs, Ralph Dibny is reading "The Young All-Stars" comic book, in particular "The Young All-Stars Vol 1 №20" issue.
 * Unlike the first three seasons, this episode has Team Flash identifying the main antagonist early on the season rather than near the end of the season.
 * Cisco refers the group of Wells as Council of Wells which is most likely a reference to Council of Ricks which serves the similar purpose in the cartoon show "Rick and Morty" for the protagonist of the show.
 * The mugger who was trying to mug Ralph and Barry is the same mugger who had tried to mug Barry in Season 1.