The combination of reddit and Japanese things gives new meaning to weird. These are, for want of a better description, miniature happy meals that you make by mixing packets of powder with water and microwaving.
This kit by Kraci and called Hamburger Popin’ Cookin’ kit DIY candy, is available on amazon. Apparently taste of the real things (burger, fries, ketchup, cola) as opposed to candy flavoured. There are other kits: sushi, donuts, cake. A 9 box bundle is also available for only $15.47 (plus shipping). Tempted for the silly fun factor.