This is the giant Hot Wheels track build by the folks at Youtube channel 5MadMovieMakers (previously: their Hot Wheels beach track, another beach track, Hot Wheels nighttime nightmare track, slow motion stunt video, this other crazy video and Thomas The Tank Engine stunt reel). It starts out of a second story window, runs along the top of a fence, and around the backyard. It does one single loopy-loop. They even send a car down the track with a camera attached so you can pretend like you're driving it. That's what I did, yelling "WE'RE ALL GONNA DIE!" the whole time. FUN FACT: Uber passengers generally will 1-star you for that, no matter how many times you offer them a phone-charging cord or a drag off your cigarette.
Keep going for the video.
Thanks to Luc, who wonders how different things might be if they'd decided to name their toys Cold Wheels instead. You wonder weird things.