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If you saw Planet 51 back in 2009, you probably remember the "inverted" premise. It’s an alien invasion movie where the "alien" is actually a human astronaut named Chuck. But the heart of the movie isn't really the guy in the space suit. It's the locals. Specifically, the characters in Planet 51 who live in a world that looks suspiciously like 1950s America, just with green skin and a lot of hovering cars.
Most people dismiss this movie as a simple Shrek-clone from Ilion Animation Studios, but when you look at the cast, it's actually stacked. You have Dwayne "The Rock" Johnson, Justin Long, Jessica Biel, and even Gary Oldman. It’s a weirdly high-budget endeavor for a movie that many people have tucked away in the "I think I remember that" corner of their brains.
Lem: The Reluctant Hero with a Dream
Lem is our protagonist. Voiced by Justin Long, he’s basically every 1950s teenager you’ve ever seen in a movie, except he’s an alien. He lives in Glipforg. He has a crush on the girl next door. He just got a job at the local planetarium. Honestly, Lem is the most relatable person in the whole film because he’s terrified of everything.
His life is orderly. Safe. Then a NASA module lands in his neighbor's backyard during a barbecue, and Captain Charles "Chuck" Baker hops out.
Lem’s character arc is actually pretty solid. He starts off as a total rule-follower. He believes the propaganda that the "Humaniacs" (their version of aliens) are brain-eating monsters. But instead of calling the army immediately, he hides Chuck. Why? Because Lem realized that Chuck is just as clueless as he is. It’s that classic "clash of cultures" trope, but handled with a lot of sincerity.
What most people miss about Lem
People often think Lem is just a sidekick to Chuck's bravado. He isn't. Lem is the one who risks his entire social standing, his new career, and his safety to help a stranger. He’s the moral compass. Without Lem, Chuck would have been dissected in about twenty minutes by General Grawl.
Captain Charles "Chuck" Baker: The "Alien" with an Ego
Dwayne Johnson voices Chuck. This was back before "The Rock" was the highest-paid actor in the world, and you can tell he’s having a blast. Chuck is an American astronaut who thinks he’s landing on an uninhabited planet to plant a flag.
He is incredibly arrogant.
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He walks out of his ship with a boombox playing "Macarena" (it was a different time, okay?) and expects to be a hero. Instead, he finds a fully functioning civilization that views him as a terrifying monster. Chuck’s growth is mostly about deflating his own ego. He has to learn that he's not the center of the universe.
Neera and the Supporting Cast of Glipforg
Neera, voiced by Jessica Biel, is Lem's love interest. For a 2009 animated film, she’s written with a bit more backbone than you’d expect. She’s part of a group that questions the status quo. While the rest of the town is panicking about the "alien" invasion, Neera is skeptical of the military’s heavy-handed response.
Then you have Skiff.
Skiff is Lem’s best friend, voiced by Seann William Scott. He’s the conspiracy theorist. Every movie like this needs one. He’s obsessed with the idea that the government is hiding things, which, in this case, they actually are. His dynamic with a robotic rover named Rover is one of the highlights of the film.
The General and the Scientist
You can’t have a 50s-inspired sci-fi flick without a paranoid military leader. Enter General Grawl. Gary Oldman brings a level of intensity to this role that honestly feels like it belongs in a much darker movie. Grawl represents the fear of the unknown. He’s not "evil" in the traditional sense; he’s just convinced that anything different is a threat to his way of life.
Professor Kipple is the other side of that coin. He’s the scientist who wants to study Chuck. Or, more accurately, he wants to take Chuck's brain out. John Cleese voices Kipple, and his performance is predictably eccentric. The tension between the military (Grawl) and the scientific community (Kipple) adds a layer of social commentary that flies over most kids' heads but keeps adults engaged.
Why the Characters in Planet 51 Feel Different
There is a specific reason these characters resonate more than your average bargain-bin animation. The script was written by Joe Stillman. If that name sounds familiar, it's because he co-wrote Shrek and Shrek 2.
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Stillman knows how to subvert tropes.
In most alien movies, the humans are the victims. Here, the green people are the victims of their own paranoia. The characters in Planet 51 are mirrors of us. They have barbecues, they go to the movies, they worry about what the neighbors think. By making the "aliens" so human, the movie makes Chuck (the human) look like the weirdo. It’s a clever flip.
Rover: The Unsung Hero
We have to talk about Rover. He’s a robotic probe sent by NASA before Chuck arrived. Rover behaves exactly like a dog. He likes rocks. He chases things. He wags his little mechanical tail.
The relationship between Rover and Skiff is the emotional glue of the second act. When Rover is captured, you actually feel bad for the hunk of metal. It’s a testament to the character design. He doesn't speak, but his movements tell you everything you need to know. He’s the R2-D2 of this universe, but with a personality that’s more Golden Retriever than sassy droid.
The Social Satire Behind the Faces
If you look closely at the background characters, the movie is a massive critique of the Red Scare era. The "Humaniacs" movies that the kids watch in the theater are parodies of The Blob and Invasion of the Body Snatchers.
The townspeople are terrified that Chuck will "infect" them with his alien ways. They think he has a "thumb" that can control minds. This absurdity highlights how ridiculous real-world xenophobia often is. The characters in Planet 51 aren't just there for laughs; they represent different facets of a society living in fear.
- Lem represents the youth who want to see the world for what it really is.
- Grawl represents the old guard who wants to keep the walls up.
- The Hippies (yes, there are protestor characters) represent the counter-culture movement.
Real-World Impact and Voice Acting Nuance
The voice cast really carries the weight here.
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Think about it. You have Justin Long using that nervous, shaky breath he does so well. It makes Lem feel vulnerable. Then you have the booming, self-assured chest voice of Dwayne Johnson. The contrast is perfect. If they had cast two generic voice actors, the movie might have fallen flat.
Even the small roles, like the two soldiers who think they’ve been "turned" into aliens because they started liking "alien" music, add to the world-building. It’s these small character beats that make Glipforg feel like a real place rather than just a movie set.
Misconceptions About the Movie
A lot of people think Planet 51 was a failure. It actually did okay at the box office, grossing over $100 million. The real "failure" was in the marketing. It was sold as a slapstick comedy for five-year-olds. While it has those elements, the character development is much more sophisticated.
Another misconception? That it's an American movie. It’s actually a Spanish-British co-production. This gives the humor a slightly different flavor than a standard DreamWorks or Pixar film. It’s a bit drier, a bit more observant of American tropes from an outside perspective.
Actionable Takeaways for Fans of the Movie
If you’re looking to revisit these characters or introduce them to someone else, here’s how to get the most out of it:
- Watch for the Easter Eggs: The movie is littered with references to Alien, 2001: A Space Odyssey, and E.T. The characters often react to these references in ways that subvert your expectations.
- Focus on the Background: The character designs of the background aliens are incredibly diverse. Notice how their clothing and hair (or lack thereof) reflect 1950s fashion trends transformed for a green, three-fingered anatomy.
- Compare Lem and Chuck: Pay attention to how their roles swap by the end. Lem becomes the brave "explorer" while Chuck realizes he’s just a guy who wants to go home.
Final Thoughts on the Glipforg Crew
The characters in Planet 51 deserve a bit more credit than history has given them. They aren't just green versions of humans; they are a satirical look at how we behave when we're scared of the "other." Lem's journey from a terrified teenager to a brave friend is a classic arc that still holds up.
If you haven't seen it in a decade, it's worth a re-watch just for the voice performances. Seeing a pre-megastar Dwayne Johnson play a bumbling, ego-driven astronaut is a trip. And seeing Gary Oldman play a paranoid general is always a treat, even in animated form.
To dive deeper into the world of Glipforg, start by re-watching the opening sequence where Chuck first lands. Pay close attention to the townspeople's reactions—it sets the tone for every character interaction that follows. You can also look up the original concept art by the Ilion Animation team to see how the character designs evolved from more "alien" forms to the familiar, suburban looks they ended up with.
Next Steps for Enthusiasts:
- Track down the Planet 51 "Behind the Scenes" featurettes to see Dwayne Johnson and Justin Long in the recording booth.
- Search for the official "The Art of Planet 51" book if you can find a used copy; it details the specific anatomy choices for the green inhabitants.
- Check out the video game tie-in if you want to explore Glipforg in an open-world setting, which allows you to interact with more minor characters not fully explored in the film.