A tiny green eggplant which I've only ever had in Thai green curry. They are usually sold - if you can find them at all - in bunches. They are the size of (guess!) peas, and look like a bunch of tiny anemic dried-up green grapes with very long stems. Pea eggplants have a peculiar bitter taste which would make them unsuitable for, say, stir-frying, but they do add a certain something to green curry. The only bitter food I had in Thailand that I liked.