Good thing the driver kept the brake on or it would have rolled back down the hill.

It was aliens. Everyone knows humans can't move heavy things.

This is the home of the ghost chile. It takes fire in the belly to pull heavy vehicles.

Speaking of aliens, their voices reminded me of this clip from Close Encounters. https://youtu.be/rugbWUnENLs

There was a moment when they were pulling it along the road that I thought they sounded like an emergency vehicle. I didn't need to watch the clip (saw the movie for the umpteenth time just recently), but agree that's a really good analogue.