The Flash hit a major milestone tonight with its 100th episode, "What's Past is Prologue", and while the episode saw some major twists in Team Flash's quest to stop Cicada it also made sure to pack in lots of clever Easter eggs as well as references to previous seasons of The CW series.
Spoilers for tonight's episode of The Flash, "What's Past is Prologue", below.
Tonight's episode saw Barry Allen/The Flash (Grant Gustin) and Nora West-Allen (Jessica Parker Kennedy) race off to various significant moment in Barry's past in order to get the items they need to for a device that would allow them to defeat Cicada. Since this is The Flash, this race to the past wasn't exactly a sweet trip down memory lane. Despite their best efforts, things quickly went somewhat awry for Nora and Barry and while that’s not great for the speedsters, it was a treat for fans thanks to all of the great references and Easter Eggs that were sprinkled throughout the episode.
In an episode as momentous as the 100th one there are bound to be a lot of little details and it's possible that we missed some, but we've put together our list of the ones that got our attention -- and a couple that caught us totally by surprised. Want to see what we picked up on? Read on for our Easter Eggs and references in "What's Past Is Prologue" and be sure to hit us up in the comments if there's a reference you saw that you think we should know about.
The list of dates
To figure out where in the past Barry and Nora would need to go, Cisco creates a list. Turns out, those aren't random dates. The dates all line up with air dates for episodes in previous seasons, specifically Season 1 (the particle accelerator explosion), Season 2 (Zoom), and Season 3 (Savitar). It's a pretty clever reference, if you ask us.
"Back in Time"
This season on The Flash is proving to be one of major discoveries for Ralph Dibny/Elongated Man (Hartley Sawyer) as he learns more and more about what it means to be part of Team Flash. Earlier in the season he learned about the concept of the Multiverse and tonight he got to experience Barry's time-travel abilities firsthand.
So, what do you do for your first experience witnessing time travel? You choose some very appropriate music, in this case "Back in Time" by Huey Lewis And The News. Not only is it an appropriate choice -- after all Barry is literally running back in time -- but it's a stellar sub-reference to Back to the Future, as the song was featured in the 1985 time travel film.
Jesse Chambers, Libby Lawrence, and Danica Williams
After accidentally breaking a key component of their Defeat Cicada plan, Barry and Nora end up having to reach out to Eobard Thawne -- in the guise of Harrison Wells -- for help. They end up revisiting a moment from Season 2, Episode 17 where Barry goes back in time to have Thawne help him solve the speed force equation.
When Thawne greets Barry and Nora, he tries to figure out who Nora is at first and name drops several DC Comics heroes in the process: Jesse Chambers, Libby Lawrence, and Danica Williams. All three women have speed-related powers. The first name, Jesse Chambers, isn't one that is unfamiliar to The Flash as Jesse Chambers Wells is better known as Jesse Quick, Harry's daughter and currently the Flash of Earth-2. Libby Lawrence is a reference to the character who, in comics, was the original Liberty Belle who married speedster Johnny Quick and is the mother of the comics version of Jesse Quick.
As for Danica Williams, that's another interesting reference. In the Justice League Beyond series, Danica Williams is the Flash of the 2040s. She is also employed at the Flash Museum and, given the timeframe, is probably someone that Nora would know.
When Thawne figured out that Nora wasn't just some random female speedster and was, in fact, Barry's daughter, he called her Dawn and then made the comment that at least Barry still had one.
While mentioning Dawn Allen alone is a curious reference, what's more interesting is that Thawne appears to mention her in the context of Dawn being Nora's twin -- and as DC Comics fans know, in comics Barry and Iris have twins Dawn and Don. Comics Dawn Allen is the mother of Jenni Ognats, also known as XS.
If by some chance Thawne calling Nora "Dawn" isn't a reference to a potentially lost West-Allen twin, it also could be a dig at the fact that Thawne killed another important Nora -- Barry's mother -- and at least he still has one Nora in his life.
Thawne and Cisco's handshake
To collect dark matter for the Cicada dampening device, Nora and Barry have to go back to the night of the STAR Labs explosion and that trip has a very unsettling reference in it. In the scene, Thawne -- again, as Wells -- shakes Cisco's (Carlos Valdes) hand. That handshake? It eerily mirrors how Thawne kills Cisco in the first season's fifteenth episode -- by vibrating his hand right into his chest and heart. Yikes.
The Legion of Super-Heroes
Back when Nora was still last season's Mystery Girl many fans thought that she might be a member of the Legion of Super-Heroes and tonight it turns out that we were right! When stepping into the time vault, Gideon mentions that Nora, as the hero XS, is the fifth recruit in the rebooted Legion at some point in the future.
While sitting vigil in Grace's hospital room, Orlin/Cicada (Chris Klein) is seen making little figures out of origami. It's a simple enough way to pass time, but it's also a clever Easter Egg. If you look carefully at the figures, they look very similar to the unicorn-like figure Deckard finds at the end of Blade Runner, something that reminds him of a comment earlier in the film that implies that Deckard is a replicant (at least in some interpretations of the scene.)
Disturbance in the (Speed) Force
Another fun movie reference in tonight's episode? Star Wars! When arriving at STAR Labs the night of the particle accelerator explosion, Nora asks why they can't just speed into the time vault instead of going the long way. Barry says that Thawne would sense prompting Nora to paraphrase Obi Wan Kenobi and note he'd feel a disturbance in the Speed Force.
The Whole Episode
Perhaps the biggest Easter Egg and reference in "What's Past is Prologue" is the whole episode itself. With Barry and Nora having to run back to so many notable points in The Flash's history, the episode is pretty much start to finish a nod to the ground the story has covered over the past five years full of snippets of familiar older scenes as well as the intriguing little details added in tonight. Even as the episode pushes this season's story forward, it also does an excellent job of looking back, making it not just a regular episode, but a treat for fans who've been along for the ride all these years.
What did you think of tonight's 100th episode of The Flash? Let us know in the comments!
The Flash airs Tuesdays at 8 p.m. ET on The CW.