Sea cucumber

They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide.
The sea cucumbers are named for their resemblance to the vegetable cucumber, but are not related to the Cucumis sativus vine.

Sea cucumbers are usually black, brown, or olive green. They have bumpy, leathery skin, embedded with bony particles.
Some-sea cucumbers have tiny tube feet along the length of their body. It is considered to be quite healthful.
It may also have something to do with its slippery feel, as the texture of food weights more heavily in Chinese cooking than other cuisines.