Cowboy Bebop and Alien have very few things in common other than they both take place in space. Cowboy Bebop is about bounty hunters traveling from planet to planet looking for a big score, while Alien is a movie about, well, an alien... that attacks a space crew. This difference, however, didn't stop the beloved anime series from paying homage to what is still considered one of the best sci-fi horror movies since its release in 1979.
In Cowboy Bebop's Episode 11, "Toys in the Attic," the bounty hunters are under attack from an unknown enemy that seems to just disappear into the dark recesses of the ship. Jet gives the viewers insight into the crew's current predicament in a voiceover: There haven't been any new bounties lately, and there is little food or money. He then loses his clothes to Faye in a rigged dice game while Spike is in the back cooking up some kabobs with a flamethrower that seems incidental, but is really a bit of foreshadowing. Jet leaves after losing his boxers, sending him to look for something to cover himself with in a back storeroom. This is where he finds an old fridge and is subsequently attacked by something.
Jet is poisoned by the bite from the creature, and while Spike analyzes the bacteria and checks it against his database, the crew speculates as to what could have caused this. Faye thinks it's a rat, Ed thinks it's a "horrible space creature," and Spike says that it could be a mutated rat. It isn't long until Faye is attacked while taking a bath, and both she and Jet fall into comas. Throughout the episode, we also get a POV from the creature itself as it uses the ventilation shafts to travel around the ship, much like the xenomorph does in the movie it takes inspiration from.
As Spike and Ed try to hunt the creature using heat-seeking goggles, Ein is attacked, making him the third victim, and Ed disappears. True to Alien, Spike is then left to look for and deal with the creature alone. He decks himself out with a net gun, smoke canisters and the flamethrower he was using to cook earlier, sets the ship to autopilot on a route to Mars, then goes out to look for the creature. He attempts to capture it with a net, another callback to the movie; sets off his gas canisters and locks the creature in the room. After a brief breather, he goes back in with his flamethrower and is able to temporarily subdue the blob of slime.
It's here that he remembers what was in the fridge and the comedic twist to the plot is revealed. He had gotten a hold of some rare Ganymede rock lobster and hid it in the fridge, but that was over a year ago. Upon opening the fridge, he is horrified by the fungal wasteland that lies within, so, naturally, Spike deactivates the gravity within the ship and simply pushes the fridge out of the airlock. But, the creature that hitched a ride on the fridge attacks him as it passes before running off into the ship again. Just as Spike is about to be sucked out of the ship along with the fridge, the door shuts, and in an homage to 2001: A Space Odyssey, we watch as the fridge drifts off into space to the music "Waltz of the Flowers." The creature is found by a sleeping Ed, who eats it, then falls back asleep. All's well that end's well.
To top it off, throughout the Cowboy Bebop episode, the creators build up the tension in a similar fashion to Alien. The little slimeball is fast and elusive, and it doesn't seem to be affected by anything. Ed is the only one not to be bitten, and had she had been, the creature would have been let loose onto Mars. This itself could have been a reference to the original ending Ridley Scott pitched for the movie, wherein Ripley's head is ripped off by the xenomorph, which mimics the voice of Dallas by saying, "I'm signing off. Hopefully, the network picks me up."
The scenes in the vents and the airlock are clear references to the movie, as Ripley also ejected the alien through the airlock door. The flamethrower is the weapon Ripley is most famously depicted with, and the idea of a creature attacking a crew in their own ship is most associated with the Alien franchise. While it wasn't the first movie to do this and won't be the last, Cowboy Bebop did a wonderful job at capturing the dread and tension the movie builds up, albeit with a more humorous ending.