In over a decade of the Marvel Cinematic Universe’s existence, Guardians of the Galaxy remains one of the franchise’s most unique and weirdest blockbusters. With an amazing soundtrack, ability to revive the Walkman, and full of equal parts heart and humor, Guardians of the Galaxy took the world by storm and popularized an incredibly obscure comic line. Rocket Raccoon (and Groot, the dynamic duo) quickly became a fan favorite. How do you not only bring a genetically enhanced raccoon to life, but also make millions of people fall in love with him?

Here are 10 off-set facts about the making of the character in the MCU:

The Real Raccoon

When animating any character, animators will first try to model the character off of something in real life. For example, PIXAR usually creates clay figures of their characters or simulated skin to animate different lighting effects. Likewise, Rocket Raccoon was based on a real raccoon named Oreo. Oreo was solely used for Rocket’s appearance rather than movements.

Unfortunately, Oreo passed away earlier this month due to illness. But he is forever immortalized in the distinctive markings of Rocket Raccoon.

The Stunt Double

As stated above, someone else provided Rocket Raccoon’s movements and mannerisms: Sean Gunn. And yes, there’s a big relation to James Gunn — they’re brothers!

For both Guardians films, Sean Gunn donned a mo-cap suit and waddled around at Rocket-height as a reference for animators. Unlike other reference actors, he could stay at Rocket’s height during an entire day of filming, making him a valuable asset to the animation team. Not only that, but he gets the character, ad-libbing this gem of a one-liner:

“Well, now I’m standing. Happy? We’re all standing now. Bunch of jackasses, standing in a circle.”

If you recognize the name already, Sean also doubles as Kraglin, the Ravager who inherits Yondu’s fin in Guardians of the Galaxy, Vol. 2.

Lip-Sync Battle

Marvel actually used two different VFX studios to animate Rocket Raccoon and Groot. Framestore was responsible for Rocket while MPC tackled Groot.

Framestore took great care in bringing Rocket to life, including fusing Sean Gunn’s mo-cap with Bradley Cooper’s voice. For the most part, the team used Cooper’s facial expressions as a guide to translate human features to a raccoon muzzle. This was done to ground the character to the viewers’ reality. It prevented him from falling into the depths of the Uncanny Valley and kept him on the same realness level as his human counterparts.

Simulated Everything

Hair—which includes fur—is one of the hardest textures to animate. Framestore had to animate both fur and clothes onto Rocket while keeping it photo-realistic enough to fit in with real people and set pieces. They wound up simulating every single hair on Rocket’s body. Keep in mind, Rocket appears in about 40 minutes of the first film. That’s a lot of time and rendering.

According to Framestore’s website, the R&D team had to overhaul Framestore’s fur system in order to process the hair, improve memory efficiency, and add color maps to each hair to replicate different hair patterns. That’s a huge undertaking for a four-foot-tall raccoon, but it does keep moving the ball forward with what animation can achieve in live action settings.

Wait, That’s Bradley Cooper?

Rocket does not sound like Bradley Cooper, end of story. Cooper impressed everyone with his vocal range and talent, proving that even live-action actors can indeed voice act. No adjustments are made to Cooper’s Rocket voice, it’s all him. And after A Star is Born, a lot more people are really believing it.

Apparently, Rocket’s voice started out as an impression of Bill the Butcher, played by Daniel Day-Lewis, from Gangs of New York. After playing it alongside an animation test, Cooper decided it wasn’t a good fit and the voice became a mix of another Day-Lewis character, Plainview from There Will Be Blood and Gilbert Gottfried.

Cooper also tried to get in character by trying to pull a Sean Gunn and recording lines on his knees. He was told to get up. That kind of method acting doesn’t translate well in the recording booth.

Mission: Breakout! Totally Counts

Located in Disney California Adventure Park and home of the late Tower of Terror, Guardians of the Galaxy - Mission: Breakout! houses one of the best animatronics the park has to offer. And a super fun attraction.

Taking place after Vol. 2, but before Infinity War, the gang’s been captured by the Collector and put on display for the general public. Rocket, the crafty trash panda that he is, manages to escape and instructs you on how to release the other Guardians, meet up with Mantis in the Milano, and let the chaos reign. Or rain. Both happen.

Each story room houses a beautifully crafted Rocket Raccoon animatronic with Bradley Cooper’s voice blasting over the speakers. The animatronic moves smoothly, hardly experiences technical difficulties, and perfectly captures Rocket’s mannerisms. The smirk is the icing on the cake. It’s a testament to the character’s popularity, as Rocket pushes the attraction’s story and theming by being the central character. Disney made no change to that decision during the short Halloween run of Monsters After Dark, with Rocket remaining the central character and the only one you truly interact with.

Superhero Origin Story

Unlike his comic book counterpart, MCU Rocket has a more tragic backstory. Instead of being genetically engineered as a peacekeeper and ending a war, Rocket was a victim of illegal genetic and cybernetic experimentation. Known as Subject 89P13, Rocket built up an impressive criminal record as well as a tendency to bite. This backstory was also explored in the Guardians of the Galaxy TV series as it’s supposed to be canon with the MCU. But since it’s run by a different creative team, your mileage may vary.

The shift in origin story better establishes Rocket’s MCU personality. His actions in Vol. 2 make a lot more sense. He’s already been through physical pain and abuse since his creation, why would he open to anyone?

No Rocket?!

That’s right. Rocket Raccoon didn’t make it into very early drafts of the movie. Nicole Perlman, co-writer of Guardians of the Galaxy, mentioned in an interview with (that has sadly been lost to time) that there were debates about including the character due to how cartoonish he might appear in the final production. Perlman initially wanted Rocket so she and Gunn could play with Rocket and Groot’s relationship and character interactions.

Thankfully, Kevin Feige, the president of Marvel Studios, actually really liked Rocket and let Perlman include him. It was a good decision since Rocket is now one of the most marketable characters of the franchise.

Heart Of The Film

James Gunn has stated that Rocket Raccoon is the heart of Guardians. Watching the first film again with that in mind, it all comes together. Rocket is a huge player, breaking the gang out of the Klyn, going after Quill and Gamora after being separated, and supporting the Nova Corp when Ronan invades.

Vol. 2 has him accepting the friendship of others outside of Groot. He starts as a slightly bigger jerk than before, then slowly begins mellowing out after a telling argument with Yondu. In the final scenes, you can tell Rocket’s taken that advice to heart, teaching us all a life lesson along the way. And you thought you wouldn’t cry during a Guardians movie.

Honoring Bill Mantlo

We wouldn’t have the movie character without his comic book counterpart. Created in 1976 by Bill Mantlo (writer) and Keith Giffin (artist), Rocket made his debut in The Sword in the Star as little more than a glorified background character. Look at him now, a major player in a multi-billion dollar film franchise.

Sadly, Bill was the victim of a hit-and-run in 1992 that left him with severe brain damage. However, he is still alive and continues to receive care. With the success of both Guardians films and a third on the way, Bill has earned an outpour of support from both fans and Marvel. According to Michael Mantlo’s column in the Hollywood Reporter, Marvel’s negotiations allowed for Bill to transfer to in-home care. On two occasions, Marvel organized private screenings of the films for Bill and most likely will continue the tradition for Guardians 3.