bikkuriman
Bikkuriman (ビックリマン) is a line of chocolate and wafer snacks produced by Lotte, made notable for the randomly assorted bonus stickers included inside each snack. First released in 1977, Bikkuriman (ビックリマン, "Surprise Man") become wildly popular in Japan with the introduction of the Akuma vs Tenshi Seal (悪魔VS天使シール, "Devil vs Angel Seal") series of stickers, leading to a prolific amount of media tie-ins.
