Let me be up front here: I don't think the Lightburn Zeta is the worst car ever made. But many people do. It's not a good car, by any standard, but it was designed to be a super-cheap, incredibly basic form of transport, and considering the context, its flaws at least make sense. That said, it is sort of delightfully ugly. And terrible.
But I'm sort of a sucker for both ugly and terrible, so you may want to take my judgement with a grain of ugly, terrible salt.
Lightburn was an Australian company that made washing machines and fiberglass boats and cement mixers, and you can sort of see influences of each of these things in the design of the Zeta. The Zeta was built between 1963 and 1966, and they only managed to sell about 400, even though they were dirt cheap at £595.
The Zeta was about as basic as you could build a car. It had a robust steel chassis, and on that a strangely overstyled fiberglass body, which got one welcome simplification and restyle in its lifespan. The side windows were perspex, the passenger's side door would open 180° to let you take out the seat and get access to the rear, since there was no rear door or hatch. They try and spin this as a plus in these ads, which I have to admire.
The engine is a 324cc 2-stroke Villers twin, making about 16 HP. It had a 4-speed gearbox, with all gears in constant mesh, driving the front wheels. It's said that it understeered, but wasn't terribly unsafe, handling-wise. The factory claimed you could hit 60 MPH, but that would probably require a direct bribe and/or sacrifice to Accleron, god of speed.
To prove the Zeta was capable enough for daily use, Lightburn did enter two into the 1964 AMPOL Around Australia Trial rally, and it finished, incredibly.
I think my favorite detail of the Zeta is the fuel guage. The Zeta used a gravity-feed system in lieu of an actual pump, and a bypass from this feed fed into a clear vertical tube that ran down the center of the dash, which was gradated and pretended to be a fuel gauge. I'm sure it could be used to see if fuel existed in the tank, no problem, but I suspect actually telling how much fuel was in there was just about impossible, unless you only drove on perfectly flat, level floors.
There was even a delightful little sports version of the Zeta, with a massive 18.5 HP engine and a body style clearly based on the Frisky microcar — even though the company claimed Michelotti designed it.
Anyway, just look at some of these promotional materials for the car and take some lessons in how to make almost anything appealing. I especially like the claims like how the Zeta's entire interior space is bigger than the largest car's trunk! That really sounds more impressive than it actually is.