The answer is in for anyone who routinely mutters, What will they think of next? Avolattes. It's a latte in an avocado and that cracking noise is either the sound of a knife hitting an avocado pit or the world splitting open to swallow you whole.
What's its purpose? Maybe it tastes good. Maybe the dishwasher took the day off. Maybe it's the creation of a feisty barista who wants to see you burn your hand. More likely, someone just wants to watch the world burn. (That seems likely since they passed up the name javacado.)