The alien ABCD (Tom Nolan), his followers EFGHI, JKLM, NOPQR, STUVWXYZ, and AEIOU (techno band Rhema), and their robot 1359 (Peter Cullen) have been searching the universe for the source of rock and roll music, and finally arrive on Earth, in the town of Speelburgh. With 1359 disguised as a fire hydrant, they set off in search of intelligent life. They meet high schooler Dee Dee (Pia Zadora), with whom ABCD promptly falls in love. Unfortunately for him, Dee Dee is dating local bad boy Frankie (Craig Sheffer), frontman of the Pack (Jimmy & the Mustangs). In a side plot, two mental patients, Chainsaw (Michael Berryman) and Breather (Wallace Merck), escape from the hospital and go on a killing spree.
Voyage of the Rock Aliens contains examples of:
- '50s Hair: Frankie has a pompadour.
- '80s Hair: Practically the entire cast.
- Air Guitar: When Dee Dee sings with the Pack, a line of backup dancers play air guitar.
- Alien Among Us: At the malt shop, the aliens clumsily attempt to pass for human by intently studying random objects and pouring condiments into their mouths.
- And Starring: Starring Pia Zadora… introducing Jimmy & the Mustangs and Ruth Gordon as The Sheriff.
- Autopsy Snack Time: A man is murdered while eating chicken. When he's wheeled into the police station, a cop pries a drumstick out of his hand and takes a bite.
- Battle of the Bands: The aliens show up at the cotillion as ABCD and the EFGHI JKLM NOPQR STUVWXYZ and pit their techno music against the Pack's '50s-style rock and roll.
- Breaking Bad News Gently: Averted.Sheriff: Am I speaking to the widow of John S. Lamont?
Mrs. Lamont: You must be mistaken. I'm not a widow.
Sheriff: The hell you're not. [hangs up]
- Chainsaw Good: Chainsaw spends most of the movie killing people, but he does have a heroic moment when he fights off the tentacle monster that's attacking Dee Dee and Frankie.
- Diegetic Switch: "Combine Man" plays while the aliens transport the pieces of ABCD, who has exploded from looking at Dee Dee, back to the ship, repair him, return to Earth, and drive to the beach on a tractor, where they play the end of the song. The beachgoers clap.
- Emotion Suppression: The aliens all have to go through an emolectomy, a procedure that removes their ability to feel emotions. It makes their lives much simpler, especially when they're doing their taxes. It does have to be refreshed after charged experiences, like a romance with an earthling.
- Genre-Busting: As James Guidotti said, "It's a little like sitting home and watching TV late on a Saturday night, all the while switching channels from 5 to 9 to 11 and to 13. On channel 5 they're airing an old beach party movie; on 9 one about alien invaders; on 11 a film about a mad, homicidal maniac on the loose; and on 13 a rock 'n' roll program."
- Human Popsicle: During their voyage, the aliens are "frozen" as plastic dolls only a few inches high. Thawing restores them to their full height.
- Hypocritical Humor: The malt shop is full of graffiti, including "Please don't write on the walls!! Mgmt."
- Insane Equals Violent: Chainsaw and Breather go around killing people, Chainsaw with a chainsaw, Breather with a knife.
- Local Hangout: The malt shop's name is Local Teenage Hangout.
- Make-Out Kids: One scene has a couple on the beach passionately making out for several minutes until the tentacle monster drags the boyfriend away.
- Mugged for Disguise: The aliens find some people making out in cars and teleport their clothes onto themselves, leaving the original owners in their underwear. The aliens don't end up keeping the costumes.
- Naughty Birdwatching: The Sheriff uses her telescope to spy on a shirtless man exercising in front of a window. While trying to focus the telescope, she accidentally jerks it upwards, allowing her to see the aliens' spaceship.
- Nothing Exciting Ever Happens Here: Dee Dee grumbles, "They should change the name of this town to Boringsville. Nothing ever happens here."
- Sdrawkcab Name: One of the planets 1359 spies on is called Acirema.
- Tantrum Throwing: Frankie is so angry to see Dee Dee singing with the Pack that he snatches a glass from someone and throws it away, smashing it.
- Unusual Euphemism: A boy invites Diane to "tickle my carburetor."
- Urine Trouble: Averted by 1359, who chases off a dog by squirting water at it.1359: Oh no, a quadruped. Look, I know what you're thinking. You leave me no choice. I'm not what you think I am. Look, it's nothing personal, I'm on a mission. It's a long story.
- Vanity License Plate: The Pack's license plate reads "THE PACK."
- Walking Shirtless Scene: Frankie spends much of the movie in an open jacket with no shirt.
- Wrench Wench: Diane is good with machinery and wears her tool belt everywhere. She's even kind enough to fix Chainsaw's chainsaw when it jams. Unlike most examples, she's quite feminine otherwise.
- You Need to Get Laid: Third-person example. Dee Dee's best friend Diane (Alison La Placa) tells her that Frankie's jerkish behavior is because of his surging hormones, and that "It'll pass, in time, as he's allowed to release his frustrations, you know, sexually speaking."