A comedy clip from @mrfatcheeto, who posts as Mr Fat Cheeto, starts with a man in a sleeveless shirt with “HVAC” lettered on his upper arm announcing that he is fixing his pickup with concrete. The caption is “I FIXED MY TRUCK DENT WITH CONCRETE,” followed by the hashtags comedy, bluecollar, concrete and bodyshop. Everything about the delivery says this is a bit, and the article treats it as one: a skit, not a repair guide.

The setting is an ordinary residential street, where a gray Chevrolet pickup is parked with its tailgate toward the camera. “Today we’re concreting our truck,” he says, then repeats it: “Today I’m fixing my truck with some concrete.” The instructions come in a mock expert voice. “First you want to get you a bucket.” He tips a bag of dry mix into a red bucket, adds water from a bottle and says “I am a trained professional.”

He stirs the mix by hand and approves of it: “That’s a good solid mix. You want it to stick to your vehicle.” Then he kneels at the rear bumper and starts smearing the wet mix across it, working it along the dented section with his bare hands. “You can see we’re bringing the bumper more flush,” he says, and a moment later, “Oh yeah, that’s looking good.”

By the middle of the video the bumper is crusted in a rough gray brown coating, and the narration turns into a body shop sales pitch. “Take that body shop. Look at it guys.” “It’s really came together.” “Oh, and it’s smooth guys.” “Oh yeah, look at it shine guys.” The frames show a lumpy surface that is nothing like smooth, which is where the joke lives.

He wraps up with a verdict: “So we successfully fixed the bumper where I hit the tree and it looks so much better, don’t it guys? Really matches the other side.” He teases another repair he says viewers will have to wait and see, then asks them to like, follow and comment, and the platform’s own like, comment, share and follow buttons appear on screen over the last seconds. The clip does not show what happens to the coating once it is left to set.

The joke only works because everyone knows concrete is the wrong material, and a few facts show how wrong. A Federal Highway Administration research report on bridge design specifications uses a unit weight of 145 pounds per cubic foot for normal weight concrete. As an illustration of the arithmetic, not a measurement of this truck, a layer one inch thick over a patch five feet wide and one foot tall comes to about 0.42 cubic feet, or around 60 pounds at that density, hanging on a bumper that was never built to carry it.

The part that is not a joke is what the clip shows his skin doing. The Occupational Safety and Health Administration says wet portland cement is caustic and abrasive, and that it can cause cement burns that may blister, harden or discolor skin and, in severe cases, reach the bone. OSHA adds that the burns may not hurt right away and can get worse after contact has ended, and that concrete, mortar, grout and stucco all contain portland cement, so they carry the same risk when wet. In the video he works with bare hands and bare arms while kneeling next to the bucket, and no gloves are visible.

For anyone who does handle wet concrete for a real job, OSHA recommends well fitting butyl or nitrile gloves, long sleeves taped to the gloves, waterproof boots, and waterproof kneepads or a dry kneeboard when kneeling. After contact, it says to rinse skin promptly with clean, cool water and a pH neutral or slightly acidic soap, and to see a health care professional for any cement burn.

If the goal is an actual bumper repair, the Federal Trade Commission’s advice for auto repairs applies. It says to shop around by phone and online, compare warranty policies on repairs, and ask for a written estimate that names the condition to be repaired, the parts needed and the expected labor charge. A shop can also tell you whether a dent like the one the creator says came from hitting a tree is a cosmetic fix or something that needs the bumper support checked.