Yes, it's apparently a cake and not a blob of water. The cake is a mixture of water and agar or gelatin, I know what you're thinking a zero calorie cake made completely out of water this is some kind of cruel joke. It is a replica of Mizu Shingen Mochi, a somewhat popular dessert amongst few in Japan and is being brought to the western world via a head chef working in New York, Darren Wong.
The raindrop cake, on its own carries zero calories and is said to have a mild water taste (doesn't all water have a mild water taste?) and is usually served with roasted soybean flour and brown sugar syrup for flavour. Mmm flavour.
The chef reported to Slate.com, that it took a lot of trial and error to get the right consistency for the cake. He had to find the right balance between mineral water and the gelatin to create the perfect water droplet effect.
He also stated that transport and distribution is a bigger hassle, as the cake has to be kept at a certain temperature for it to maintain its look, movements can also alter its sleek presentation.
For the adventurous type or the people who like their water to have a little chew to it, you can find the Raindrop Cake at New York's Smorgasburg. For those who would like to make their own rendition of the Raindrop Cake watch the below videos.