Konnayku, also known as Konjac, konjak, konjaku, devil's tongue, voodoo lily, snake palm, or elephant yam (though this name is also used for A. paeoniifolius), is a plant of the genus Amorphophallus. It is native to warm subtropical to tropical eastern Asia, from Japan and China south to Indonesia.
It is a perennial plant, growing from a large corm up to 25 cm in diameter. The single leaf is up to 1.3 m across, bipinnate, and divided into numerous leaflets. The flowers are produced on a spathe enclosed by a dark purple spadix up to 55 cm long.
The food made from the root of this plant is widely known in English by its Japanese name, konnyaku (yam cake). The two basic types of cake are white and black. Pushing the cake through a grid of sharp blades at the end of a wooden box gives noodles, called shirataki, which are also sold in white and black colors.
The corm of the konjac is often colloquially referred to as a yam, although it bears no marked relation to tubers of the family Dioscoreaceae.