Principle for Mac ($99) is a tool for designing animation, primarily for mobile devices. It provides an easy to use interface for prototyping interaction, transitions, or other animated elements in your interface.
You can design with text, rectangles (which can modified with border radius to make circles), or graphics created with other tools, and then hook up animations for actions like taps, scrolling, and drag, and use the drivers UI to connect those actions to drive other properties. An animation UI gives you control over timing and easing for specific transitions, but the defaults also work well without customization. Really nice.
In the prototype window, you can test out your actions and animations. Pressing the video icon will record the session and allow you to export as a .mov file or animated gif.