Rest stops in Japan tend to be a little different from their western counterparts. Aside from offering drivers a chance to stretch their legs and powder their noses, they often offer unique goods characteristic of the area. Sometimes the rest stops are even the final destinations for summer road trips.
A perfect example of a unique rest stop is the Ranzan Parking Area (RPA) in Saitama prefecture along the Kanetsu Expressway. Here you can get your hands on two specialty dishes, ice cream and curry, both black as midnight.
And before you say it: no, neither dishes use squid ink.