It is called Pudding
Jake Shake, a drinkable version of caramel pudding made with Hokkaido cream. It seemed quite a solid mixture after having been in the refrigerator but if you shake it up 5 times as directed on the cap it becomes more of a liquid.
JakeShake can be found at http://www.pokka.co.jp/pudding/ It retails for YEN 180.
I don’t think I would be a regular drinker of Pudding
JakeShake, but it was good to try it.
As with many products in Japan recently it has the 3D bar code mark on it so that mobile phones can easily scan the product and jump to a related website.
I picked this Pudding up at my local ampm
Update: Thanks to topaz for the correction on the naming of Pudding Shake – May 11, 2009