Sounds like the old How Many People Can You Fit In A Mini. We got a motorcycle into one - took the seats out, took the wheels off the Husky 250 and put it in, no room for a passenger.
My Nissan NX Coupe was pretty small, but was big in the back. When I used to do my daughters lawns, I'd put my mower and weedeater in the back rather than use the trailer. I also fitted a plastic 209 litre (50 gal) drum back there, and a 180 litre hot water cyl...that was a real close fit, right up to the dash and touching the rear screen.
I know my Volvo 850 can take a coffin...mind you, I've also seen a coffin in a Mini van.