We've traveled to Indonesia years ago and there was this ingredient I had never tasted before which has had me looking for years. I had it in gado-gado many times there, including in an Indonesian restaurant in North America which had me very nostalgic!
I don't know what the original vegetable looks like but cooked, it was a pale green. I saw it served in many different shapes crescent-like, julienne, or diced, so I figure it may be some kind of squash but it didn't really taste like any squash that I know of.