"Welcome to the Dollhouse"/"Game On, Charles" (Season 5, Episode 25)/(Season 6, Episode 1)
This brilliant pair of episodes — in which Charles locks the Liars in a dollhouse for weeks in cells that look exactly like their childhood bedrooms — encapsulates everything PLL does best: Eerie doll motifs, psychological torture, and the feeling that you’ve stumbled into some sort of tech savvy Twilight Zone reboot. Taken together, the episodes almost feel like a standalone movie.
"Shadow Play" (Season 4, Episode 19)
This season 4 episode is truly unlike anything else the show ever did. When Spencer pops too many pills, viewers are treated to a show inside her mind, which pulls Rosewood into the black-and-white world of film noir. Arguably the show’s most creative hour, “Shadow Play” stands out from the rest.
"This Is a Dark Ride"(Season 3, Episode 13)
Pretty Little Liars always went big when it came to Halloween episodes, but nothing is more memorable than that time Adam Lambert performed on a moving train and Aria found herself trapped in a box with Garrett’s dead body. Did we mention that her friends saved her from sure-death when said box was almost thrown off the train? Talk about a dark ride.
"A dAngerous gAme" (Season 3, Episode 24)
Everything changed after the fire in “A dAngerous gAme.” Not only did Red Coat save the Liars from certain death, pulling them out of the burning building, but the whole premise of the show was flipped on its head when it appeared that Ali, star of Pretty Little Liars’ central murder, was actually alive. Although it wouldn’t be confirmed until season 4, this twist is still one of the biggest risks PLL has ever taken.
"Last Dance" (Season 6, Episode 9)
Three words: Drunk basement moms. But if that’s not enough, “Last Dance” is better known as the show’s most exciting prom episode. The highly suspenseful hour involves a number of PLL staples: Mystery, horror, beautiful dresses, and in the episode’s final moments, a reveal as Charles (or, as we’d later learn, Charlotte) meets with Alison, face-to-face.
"UnmAsked" (Season 2, Episode 25)
Remember back in the season 2 finale when we thought there was just one “A,” and we were momentarily shocked — and relieved — to find out it was Mona? Then Mona asked Spencer to join the A-Team, and we also found out Mona answered to someone even higher. The mystery we thought was finally solved was only just beginning. Still, the Mona reveal was a great one.
"Now You See Me, Now You Don't" (Season 4, Episode 12)
Two red coats. Emily is nearly sawed in half. Ali is alive?! And, the biggest shock of all … Ezra is “A”?! This hour packed so many punches it’s practically a TKO. When the Liars head to Ravenswood looking for answers, Mrs. Grunwald tells them the truth about the night Ali was buried alive: Grunwald saved her life, a fact that confirmed Ali was among the living. Add on the Ezra reveal, and you have one of PLL‘s most shocking episodes.
"Grave New World" (Season 4, Episode 13)
Immediately following “Now You See Me, Now You Don’t,” the Liars attend an all-time creepy Halloween party in Ravenswood before realizing that Mrs. Grunwald was right when Alison DiLaurentis makes her return, in a red coat and all.
"Game Over Charles" (Season 6, Episode 10)
Charles DiLaurentis’ reveal as transgender woman Charlotte — better known to us as CeCe Drake — was polarizing for fans, but still a landmark unmasking. No matter where you stand on the Charlotte issue, though, you’ve got to hand it to actress Vanessa Ray, who did an excellent job unspooling Charles’s sad and sordid history.
"Miss Me x 100" (Season 5, Episode 5)
PLL did its 100th episode big: Not only does Ali admit she might possibly have feelings for Emily, but Aria and Ezra get back together, Spencer and Toby get closer, and Hanna realizes she needs to ditch Travis for Caleb, newly-returned from Ravenswood. Of course, such happy reunions couldn’t stand for very long in Rosewood, and as the gang gathers in Emily’s living room to watch a press conference about Bethany Young’s body being identified … the Cavanaugh house explodes down the street.