It looks like a harmless 1966 GMC Handivan hiding a whiskey still, but it's really a 40-year-old antecedent to modern fuel-cell vehicles. It's the GM Electrovan, one of the first experiments in using hydrogen to propel a car — a swashbuckling exercise marked by exploding storage tanks, leaking electrolytes producing brilliant sparks and strange orders to GM's purchasing department for fire retardant and a horse trough big enough "for a man to lie down in." It was based on a similar system used in Gemini spacecraft, which produced drinking water for astronauts in addition to electrical current. Unfortunately it required lots of precious metals as well as highly pressurized hydrogen and oxygen (modern systems can use outside air), and the space of a van to install, and the project was abandoned. Now, the ominous-looking prototype is on display as part of the Petersen Museum's "Propulsion after Petroleum" exhibit as a long-forgotten artifact that allows GM bragging rights as the first developer of hydrogen cars.
Petersen Museum to Feature History of Alternative Propulsion [internal]