In the dead of summer, it gets hot. You can cool off with some A/C, by jumping in a pool, or, if you're in Japan, by applying some of this spray can coolant.
Much like silly string, this weird foam in a can comes out and lets you spray it anywhere. But unlike silly string, it comes out ice cold, allowing salarymen to make chilly foam bracelets or necklaces to keep them cool in the dead of summer.
OK, why is this popular in Japan but not over here? Come on, someone import a few crates of this and make some money.