Guard Dog is a 2004 animated short film (five minutes) by Bill Plympton and the first of his Dog series.
It seeks to answer the question, why do dogs bark at innocuous things? The story takes place from the POV of a dog going on a walk with his master. The dog is a cheerful fellow who hops along with his tongue hanging out. However, any time the dog sees anything at all—a little girl, a squirrel, a groundhog, a cricket—the dog imagines that thing murdering its master in an over-the-top gory way.
- Art Evolution: One of Plympton's first shorts to use digital compositing to overlay character animation into the backgrounds, as opposed to cutting and pasting the characters onto cels or redrawing backgrounds for every frame.
- Black Comedy: The dog imagines various creatures murdering its master in all sorts of ridiculous gory ways (the squirrel pours gasoline down the man's throat and turns him into a Roman candle). Then the dog itself accidentally kills the man by strangling him with its leash.
- Eye Scream: The Imagine Spot with the cricket has the cricket jumping inside the man's head, and then kicking out the man's eyeballs from the inside.
- Imagine Spot: The dog has a very active imagination. When it sees a bird in a nest, it imagines the bird as a ninja which turns its next into a throwing star and flings it at the man. When it sees a flower, the dog imagines the flower wrapping the man up like a boa constrictor and then shooting pollen into the man's face, causing the man to cough himself inside out.
- Irony: The dog spends the whole cartoon imagining ridiculous over-the-top ways for little girls or squirrels or flowers to kill its master. But in the end, the dog's overexcited yipping and chasing around winds up wrapping its leash around the man's neck, and the dog strangles the man to death.
- Off-into-the-Distance Ending: The cartoon ends with the dog slowly dragging its master's corpse away.
- Red Eyes, Take Warning: When the dog imagines the animals turning into murderous maniacs, the animals' eyes always turn red.
- Scare Chord: The cheerful walk-in-the-park soundtrack always transitions to a Scare Chord when the dog sees some innocuous creature and imagines it murdering the dog's master.
- Silence Is Golden: No dialogue, only a cheerful soundtrack and the barking and panting of the dog.
- Xenofiction: A cartoon short told from the POV of an excitable, overimaginative dog.