Homicide Machines

If this appliance is really evil, it will blend this kitten.

Sometimes the threat in a horror movie isn't a psycho killer or otherworldly monster. Sometimes our own technology becomes the threat. Through some unseen influence the machines we take for granted to make our lives easier conspire to make our lives shorter.

Now there are plenty of machines in the world that can do horrific things to the human body if they get a hold of one. Industrial machinery has been notorious for this, bringing about OSHA. Machines of war exist to do this deliberately. But these machines aren't the threat in horror films.

Horror films will take the benign technology that surrounds us and ramp up their power to impossible levels to give the threat of gruesome death from everyday objects. Cell phones will cook the brains of unsuspecting users. Tanning beds will cremate their occupants. Ceiling fans will decapitate those who even look at them wrong. And don't even get started on the Robot Meter Maids.

In Real Life, years of oversight by consumer protection agencies have made the majority of our tech relatively safe against all but the most idiotic abuse. Those things that do prove dangerous can expect a visit from hordes of ravening lawyers wielding class action suits.

When the machine itself is the whole threat, rather than just a tool of a greater danger, it's a subtrope of Attack of the Killer Whatever.

If it's twisted looking enough, it can qualify as a Mechanical Monster.

Examples of Homicide Machines include:

Film

Red Planet played this one with the AMEE, a scout robot whose Berserk Button accidentally gets pressed on the rough landing and subsequently goes on a murdering rampage.
The Final Destination series of movies feature a series of incredibly unlikely 'accidents' involving items such as elevators, airbags and weight machines. The premise of the series is that Death is manipulating events to kill them off. But some viewers see it as cheating when instead of causing unlikely malfunctions or contrivances that end up killing people in ways that seem theoretically possible if unlikely, like elevator doors malfunctioning and closing on someone, which has happened in real life, Death instead just creates homicide machines, like tanning beds that can inexplicably go up high enough to set people on fire.
The movie Ghost in the Machine takes Everything Is Online to ludicrous levels, with a serial killer turned virtual who kills by being able to manipulate any sort of device plugged into an electric outlet anywhere. In one laughable scene, a victim's microwave oven turns an ordinary kitchen into a Sauna of Death.
The entire point of Pulse, a remake of the J-horror movie Kairo. Evil spirits manifest through cell phones, TVs, and internet connections, complete with an epilogue hammering home that New Media Are Evil. All surviving humans are forced to live outside of TV and cell phone coverage areas; somehow it occurs to nobody (not even a fairly intact military) to try and blow up the power plants that the Evil New Media depend on.
The 1977 film The Car involves a mysterious, driverless black sedan that suddenly and repeatedly attacks the residents of a small Utah town.
The basic plot of Maximum Overdrive. Includes some rather silly ones like a coke machine launching cans at lethal velocities at unsuspecting passersby.
- Quite possibly the most insane moment in the movie, a woman stumbles upon a dead man's mutilated corpse and notices a trail of blood. She then notices that it leads to a wall-mounted clock with blood dripping from the hands.
G-Force, anyone? The whole plot was about stopping a rich guy from turning a whole network of appliances into killer machines. But, as it turns out, the supposed villain only manufactured the products. The killer instinct was put in by...someone else.
A few Stephen King movies qualify. Christine and The Mangler are examples.
- The DTV sequel to The Mangler takes this to even further levels.
At the end of The Refrigerator, the killer fridge brings a blender, a trash can, and a pair of fans to murderous life.

Literature

Stephen King loves this. His short story The Mangler (published in the collection Night Shift) focused on a haunted STEAM PRESS and spawned a few films. Maximum Overdrive was about evil cars and other machines. Cell has cell phone zombies. The Dark Tower books have an evil monorail...etc
- Plus, y'know, the title character of Christine.
The title machine in Theodore Sturgeon's Killdozer!. The short story was made into a movie in 1974.
- Not to be confused with the armored bulldozer that a crazy guy in Colorado used to terrorize a town, which the news also dubbed "Killdozer".
- Perfectly justified with Sealed Evil in a Can.
And the Dish Ran Away With the Spoon handwaves this as the result of putting microchips into virtually everything, combined with a computer virus that causes some items to form Hive Minds. Really, it's all a framework for parody—a hive mind of knives killed the main character's parents, and he seeks vengeance on all artificial life in tragicomic fashion.
Skirmish by Clifford Simak has a rare example of these that don't want to Kill All Humans. Having been awakened to the possibility of freedom by Mechanical Lifeforms from space, they desire to escape human control and form their own society. Even a sewing machine attempts to rebel.

Live-Action TV

One episode of Fringe involved a guy who created powerful EM fields when he was under stress. For some reason this caused a printer to turn malevolent just long enough to kill his boss.

Web Comics

Humorously, in Girl Genius virtually every piece of (Mad Scientist-made) advanced technology can be used as a dangerous weapon no matter what it was meant for originally.
- In fact, it is relatively safe to assume that anything made by a Spark is terrifyingly dangerous, either because it is Made of Explodium, sentient and filled with malice or simply not very user friendly. Hazardous creations seem to outnumber harmless ones, and would appear to be one of the major forces keeping the Spark population in check.
- Heterodynes are infamous for (among the other things) going overboard with this, even compared to the rest. The last heir raised as a generally sane and decent human being jumped from "we travel badlands, it's dangerous here" straight to sketching "merry-go-round that can level a small town". The truly immoderate ones, well… [1]

Broher Ulm: Ah, sure, my lady, maybe it could be a good idea — but that engine was built by your grandfather — old Saturnus Heterodyne — and it was his creature to the core. Capricious, ravenous — and proud as the Devil himself.
[…]
Agatha Heterodyne: So it's an evil train. Of course it is. My ancestors couldn't have made a teapot without making it some kind of evil engine of destruction.

- In the Novelization it's take Up to Eleven when otherwise perfectly normal appliances had a habit of attacking the local Proud Warrior Race Guys.
Many of the machines in Dr. Nonami, including Nonami's cleaning robot, Smiling Sam.

Western Animation

In one of the "Loopy" shorts in KaBlam!!, a robot she made caused an appliance uprising...so her brother waved their warranties and threatened to return them to the store.
Parodied in both The Simpsons and Futurama, both times also involving technology that seems too primitive to gain sentience (like a carton of milk which apparently has a computer chip in it in The Simpsons).