Arrow's 150th episode didn't just give us a hilarious documentary-style hour, it also gave us, like, all the cameos ever.

The camera crew that filmed "The Emerald Archer" documentary may have gotten most of their footage by following Oliver (Stephen Amell) and crew around, but they'd apparently been working on this project for years. So naturally, they had interviews from quite a few people we thought were long gone. The episode opened on Quentin Lance (Paul Blackthorne) circa 2014, and honestly, if you didn't realize right then and there that the episode was going to send you into a fit of joy, you're watching Arrow wrong.

Other interviewees included Thea Queen (Willa Holland), Sara Lance (Caity Lotz), Sin (Bex Taylor-Klaus), Rory Regan (Joe DiNicol), Roy Harper (Colton Haynes) and early Season 1 Diggle (David Ramsey)! Yeah, that interview about how Oliver was no one's hero really didn't age well. To top it off, we even got an interview with Barry Allen (Grant Gustin)! Yep, this episode was also a stealth crossover, wherein Barry tried valiantly to pretend like he was shocked, shocked I say, that Oliver had turned out to be the Green Arrow. It's impossible not to love that doof.

Meanwhile, one person who wasn't psyched to appear in the documentary was the newly returned William (Jack Moore), who had been kicked out of boarding school. When he threw some serious 'tude Felicity's (Emily Bett Rickards) way, he admitted he was pissed off that Oliver hadn't asked him to come home during the holidays, choosing instead to exile him at boarding school. We sense there's more to this story, like the real reason he was expelled for instance, but mostly we were just glad to see Mama Felicity back in action.

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At the end of the day, the villain they were hunting turned out to be a vigilante fan who was attacking the crime-fighters so he could steal their masks for his shrine. Fans can be... intense. But hey, without them, Arrow wouldn't have 150 episodes under its belt, so it's kind of a mixed bag.

This latest scuffle ended up forcing Rene (Rick Gonzalez), Curtis (Echo Kellum) and Dinah (Juliana Harkavy) back into their vigilante masks, which should have been enough to land them in prison because of the Anti-Vigilante Law. Instead, the mayor decided to deputize them like Oliver so that they could legally protect the citizens of Star City. Team Arrow is back, y'all!

Meanwhile, 20 years in the future, Maya (Katherine McNamara) appeared to be kicking off an agenda of her own after watching this illuminating little documentary. Together with Connor Hawke (Joseph David Jones) — who we have several questions about, by the way — she tracked down the old Arrow cave, which had fallen into ruin after years of being abandoned. Unfortunately, Maya seems to be in the anti-vigilante club, since she told Connor that these vigilantes got everything they deserved.

Um whoa. Harsh much?

Arrow airs Mondays at 8/7c on The CW.

(Disclosure: TV Guide is owned by CBS, one of The CW's parent companies.)

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Stephen Amell and Emily Bett Rickards, <em>Arrow</em>Stephen Amell and Emily Bett Rickards, Arrow