Every Halloween gets the monster it deserves. Vampires, zombies, the occasional killer doll. In 2026 the scariest thing in town is a beige building with no windows that showed up by the highway, promised a few dozen jobs and started humming at three in the morning.
We’re talking about the AI data center. Nothing frightens a neighborhood right now quite like one, and nothing makes a better costume, because the real thing is basically a cardboard box with a cooling bill. Out in Hillsboro, west of Portland, whole blocks of them sit behind fences and berms and somehow manage to look like nothing at all. So we worked out how to build one. Bring a fridge box.
What you’ll need
Most of this is already in your garage or your recycling bin.
- One large appliance box. A refrigerator box is ideal; ask nicely at the hardware store
- Two smaller boxes for the cooling units
- A quart of grey or tan paint, roughly the color of a strip mall dentist
- Two small battery fans
- About six feet of silver dryer duct
- A strand of tiny green and amber LED lights
- A roll of plastic garden fencing and a hula hoop
- A small Bluetooth speaker
- A clipboard of signed NDAs (optional, highly recommended)
- The biggest water bottle you can find. Bigger than that. No, bigger.
How to build it
Give it one evening and two adults, one with the box cutter and one with the roller.
- Cut the box. A hole for the head, two for the arms. Do not add windows. A data center has no windows, and for one night neither does your child.
- Paint it. Two coats of the grey. Resist any urge to make it pretty. The real ones are designed to be forgotten, and if a neighbor can describe yours afterward, you’ve failed.
- Add the cooling. Glue the small boxes to the shoulders, draw grilles on them in black marker and mount the fans inside. Run the dryer duct from one shoulder to the other for no clear reason. This is the part everyone at the party will love.
- Rack the servers. Draw rows of slots down the front and poke the LEDs through. Let them blink at random. Nobody knows what the lights mean, including the people who installed them.
- Fence it in. Zip tie the garden fencing around the hula hoop and wear it at the waist. Add a hand-lettered sign: JOBS COMING SOON!
- Install the hum. Hide the speaker inside and play the hum below on repeat. Set the volume so adults can feel it but can’t quite tell where it’s coming from. Leave it on in the car. Leave it on all night.
The hum is the costume
Anyone can wear a grey box. The hum is what sells it. Neighbors of new data centers from New Jersey to Wisconsin to Utah describe the same thing: a constant low drone, day and night, that gets into bedrooms and backyards. A class action filed this summer against Microsoft’s new campus in Mount Pleasant, Wisconsin, argues that much of that hum is low-frequency infrasound that ordinary decibel readings don’t even catch.
So we made you one. The track below is a one-minute loop of electrical drone, slow beating tones and fan air, built from scratch so a small speaker can actually play it. It’s no infrasound, but it’s close enough to unsettle a porch. And when anyone complains, your trick-or-treater has the perfect line: “We are operating within local ordinance.” Then they turn it up.
Hydrate like you mean it
Every data center needs a cooling supply, so the costume isn’t complete without water. Lots of it. Hand your kid the largest jug in the house (a five-gallon office cooler bottle with a bendy straw is the dream) and give one instruction: drink constantly, and ask for a refill at every door.
They won’t keep up with the real thing. Researchers at United Nations University estimate that data centers worldwide went through about 4.5 trillion liters of water in 2025, and expect that to roughly double by 2030. But encourage the effort. When the jug runs dry, they should ask the neighbors for theirs. When the neighbors say no, they should ask the city council.
How to stay in character
The paint job matters less than the attitude.
- Arrive without warning. Data centers don’t knock. They appear on a zoning agenda at 4pm on a Tuesday.
- Ask for more candy than any other house on the block, at a discount.
- Promise every porch “hundreds of jobs.” Deliver four.
- When an adult asks what’s inside, say “proprietary.”
- Never go to sleep. Neither will anyone within a mile.
Make it a group costume
One data center is a costume. A whole family of them is a zoning variance.
- The toddler: an Edge Node. One shoebox, one blinking light. Still hums.
- The tall one: the substation. Cardboard transformer, three paper towel tubes for insulators, lots of yellow warning stickers.
- The parents: the two people who live closest to it, in bathrobes, holding a petition and a very large coffee.
- The dog: a backup diesel generator that kicks on at 2am. You may already own one.
- The friend group: Data Center Alley. Five kids in identical grey boxes walking in a line. Nobody can tell them apart.
Carve the data center
For the porch, a free stencil: two cooling fans for eyes, a vent for a nose and a grin full of drive bays. Black gets cut out, grey gets scraped so the hum lines glow, and the three little server lights get poked through with a skewer.
It prints on letter paper and fits a medium pumpkin about nine inches wide.
The best part of this costume is the ending. Unlike the real thing, it comes down on November 1st and goes in the recycling. Send us a photo of yours, or tag @mossandfog! Just keep the speaker down after ten. In Vineland, New Jersey, county health officials cited a data center for noise over 50 decibels between 10pm and 7am.
Still not scared enough? Meet Bezzy, the data center plushie that screams when you hug it, then settle in with the 31 best horror movie posters ever made.
