The "Floating Dot" that gives extra information

I don't even know what it's called, but I'm seeing it show up in a few mobile apps, and some standard web pages, as well. Facebook has a "talking heads" version of it, and even Google is on board with their inbox "plus" thing.

It's a "dot" for lack of a better term, often draggable to other parts of the screen, 50-100px wide, with a tooltip of some kind saying "Click on me to see some of your choices" or something to that effect. If you click on it, it either expands or prompts a modal, or does some specific action. It's kinda out of the way, but easy to access as necessary.

Does that thing have a name? Is there a free library that creates it? I'd like to implement something similar for a project of mine but I don't even know what to call it.