Konnyaku jelly is a gelatin made from konnyaku powder, which in turn comes from the konjac root (aka Devil’s Tongue Yam.)
It doesn’t dissolve in the mouth as quickly as regular gelatin. You need to chew it, like a gummy bear.
It is often sold prepared as small, bite-sized moulded jellies in plastic trays or cups, or prepared as candies. Usually fruit-flavouring is added.
To make jelly from the powder, you mix konnyaku powder with sugar, add to cold water in a pot, bring just to a boil, then remove from heat and stir for about 5 minutes. Then add any colouring and flavouring you want, and pour into moulds, then put into fridge to set.
Konnyaku Jelly was very fashionable in Malaysia in the late 1990s — many cooking schools ran courses just on how to make it.