This is a Japanese food named ‘konnyaku’ or ‘konjac’. It is made from the starch of a type of taro. This taro is called ‘devil’s tongue’ in English (an interesting name!). Although konnyaku is a very popular food in Japan, even Japanese (especially young people) hardly know what it is made from.
Konnyaku is eaten throughout the year. But I feel closer to this food when it is cold. Because it is a popular ingredient in a hot pot dish ‘oden’, the dish like a picture below. Most convenience stores begin to sell it at the side of the register counter at the end of summer. If you smell of something good there, ‘oden’ must be its source! Convenience stores compete with each other over the taste of ‘oden’.