Doner kebab
Döner kebab in Cologne, Germany. Alex Kehr

Polish students have invented what could be the world's very first vending machine for that most beloved post-pub treat, the doner kebab.

Students at the Warsaw University of Technology have been crowding excitedly around the new machine since a team from the Faculty of Automotive and Machinery Engineering revealed their invention. They spent two years working on the innovative project, which Radio Eska in Poland claimed was definitely the first in the country and probably the first in the entire world.

The Kebs & GO project works by having kebabs prepared twice a day at a restaurant, before they are stored and refrigerated in the vending machine. When someone orders a kebab, which costs 10 zł (£2.11), it is heated up and dispensed four minutes later.

Two types of kebab meat, beef and chicken, are currently sold in the machine, along with mild and spicy sauces. According to Eska, the inventors have promised that a vegan or vegetarian kebab option could be coming soon.

Although a kebab vending machine has not been invented before, there have been other weird and wonderful versions of the snack dispensers.

In 2012, a caviar vending machine, which gives customers 28g (an ounce) of the fanciest Imperial River Beluga caviar for $500 (£375.77), was launched at malls across LA. There are cheaper options though, as the machine will also dispense American Black Caviar for $30. The creators had to get temperature, oxygen, moisture, ventilation and lighting levels to work perfectly. It is also possibly the vending machine with the tightest security in the world, including no less than three cameras, due to the pricey contents.

The Australians invented a hot chip vending machine which take about two minutes to cook. Peter Malone, the CEO of the Hot Chips Company, told Radio 6PR in 2016 that there is no risk of the machine setting alight because it uses brown rice oil, the "safest" possible, and crucial electronic processes turn themselves off if it is knocked over.

But perhaps the weirdest type of vending machine yet are those one serving up live crabs in China, which began to appear in 2010. Mr Liu, who owns a vending machine and the crab shop next door in Hangzhou, told City Express in 2013 the idea was to capture after-hours demand. "Crab shops like ours, they generally close at night," he said. "But what are people to do at night when their stomach starts to feel empty and they want to chow down on a hairy crab and knock back some booze?"

Mr Liu's vending machine dishes out crabs with crab vinegar and two bags of ginger tea for around 20 yuan (£2.27, $3.03), and is restocked daily. Other dispensers around China varied in price from 10 yuan to 50 yuan, depending on the size and gender of the crab.

Live crab vending machine
Live hairy crabs are displayed in a vending machine at a main subway station in Nanjing, Jiangsu province in December 2010. REUTERS/Sean Yong