Could this limited edition iPhone 5 case save your life?

Japan's enthusiastic attitude to all things technology-based produces a healthy amount of giggles in forward-looking circles, but the country's latest claim to fame is one of the wackiest nerdy endeavours we've seen to date.

Taking the notion of survival-standard mobile accessories to a hilarious extreme, the "Survival Senbei iPhone 5 case" is an edible handset sleeve made from toasted brown rice and is a playful take on a popular traditional drinking snack - senbei is the UK equivalent of the pork scratching, if you like.

Sold on the chopstick-in-cheek basis that it offers a potentially life-saving source of nutrition in the event of a disaster, the case retails for ¥3,818 (nearly £30) and is apparently quite an exclusive bit of kit – the artisan senbei-maker responsible for the cases can only churn out around three products a day, so presumably you'll be the coolest kid in the cat café if you can get your hands on one.

Its usability as an iPhone protector seems to be equally limited, however, with the company responsible for the PR gag pre-emptively addressing complaints by pointing out a number of situations in which the case is likely to break - these include being fixed to the iPhone 5 (75 per cent chance), using the touch-screen (18 per cent), putting the handset into your pocket (89 per cent) and being dropped (120 per cent).

In other words, the likelihood of it surviving a desert island plane crash isn't exactly assured, but we're sure that if does emerge from the wreckage, it would make an immensely tasty treat and admirable partner to the local cannibals' craft beverage of choice.