Skeletonized leaves are not terribly rare, but this lace-like skeletonized flower is the first one I've ever seen, and despite its ghostly transparency and veiny, deathlike appearance, it was still soft and alive. Adding to its creepiness, I found it growing near an old Hawaiian burial site.
The skeleton flower is that of a White Lady (Thunbergia fragrans), and normally this vine's 2 inch (5 cm) wide flowers are a solid white color. Although they are attractive, the flowers are short-lived and wilt by late afternoon. This particular White Lady flower was photographed in the morning, so I don't know why it was in such sad shape.
Here in Hawaii, White Ladies grow in windward coastal areas, and their shining white flowers are a common sight along roadways.