The cartoon starts as the neighborhood's cat owners all (literally) throw their cats out for the night. Porky Pig attempts to do the same to his four cats, but they turn on him and throw him out into the snow. Porky bangs on the door, demanding to be let in, but the cats pop out of the door and proclaim in unison, "Milkman, keep those bottles quiet!", and then slam the door in his face which soon leads to a battle between Porky and his cats for the house for the rest of the cartoon.
The cartoon is notably a runner-up on The 50 Greatest Cartoons list.
- Alien Invasion: The cats disguise themselves as aliens and trick Porky into thinking Earth is being invaded by Martians.
- Bowdlerization: Versions shown on FOX's Merrie Melodies Show and The WB in America and the United Kingdom's BBC channel cut the scene where the cats smoke cigars, read comics, lounge, and drink wine before Porky bursts in on them.
- Breaking the Fourth Wall: In the ending, Porky turns to the camera and asks the audience if they have a vacancy for a house.
- Crazy-Prepared: Porky has a glass case with a gun in it, specifically labeled that it's for use only in case of an invasion from Mars.
- Deranged Animation: Since the cartoon was made at the peak of Clampett's directing abilities, the animation is extremely wild even by his standards. And as pointed out here, the cartoon deliberately plays fast and loose with the perspective of both the characters and the backgrounds for truly surrealistic effect—the perspective is deliberately wonky and off on almost every single background and often falls back on forced perspective, with the lines seldom adhering to a vanishing point, and what's more, the characters are often animated as if they were performing in front of a flat background. It even goes as far as switching a background in the middle of a scene to heighten the impact of a cat smashing his head into a door.
- Downer Ending: Porky fails to reclaim his house from his cats and is forced to seek vacancy elsewhere. It's Played for Laughs, though.
- Impossible Shadow Puppets: Porky uses this to create the shadow of a dog to scare away the cats.
- Oh, Crap!: Porky freaks out when he catches on that aliens (the cats in disguise) are sharing his bed.
- Again, when the cats (dressed as the Rough Riders) charge at him.
- Rhetorical Question Blunder:Sylvester: Are we men, or are we mice?
Small cat: I like cheese.
- Roll Out the Red Carpet: In the opening, a butler of a rich cat owner rolls out a red carpet into the show before kicking out the cat.
- Saying Sound Effects Out Loud: When Sylvester is giving a Rousing Speech to his fellow cats, rhetorically asking, "Are we men, or are we mice?!" the little cat says, "I like cheese," to which Sylvester replies, "Smack!" as he slaps the kitten.
- Shout-Out: There are several pop culture references in the cartoon:
- "Milkman, Keep Those Bottles Quiet" was a World War II hit song by Ella Mae Morse, and was sung by Nancy Walker in the movie Broadway Rhythm.
- The wine that the grey drunken cat was drinking says "Arsenic and Old Grapes" as a parody to Arsenic and Old Lace.
- Porky calls for Lassie to scare off the cats.
- The "Men from Mars" scene is a reference to the Orson Welles' infamous War of the Worlds radio broadcast.
- The cats charging at Porky assume the appearances of Theodore Roosevelt and his Rough Riders cavalry, which is a reference to the then-popular film Arsenic and Old Lace.
- One of the cats is a parody of Spooky the Cat from Bil Holman's Smokey Stover comic strip.
- Toilet Teleportation: One of the cats escapes the house by pulling on the drain plug of Porky's sink and getting flushed down with the water.Cat: Geronimo!
- Wild Take:
- Porky has this reaction when he realizes there are "martians" sleeping in bed next to him.
- The cats also do wild takes when Porky surprises them.