This position paper argues that earphones hold the potential for major disruptions in mobile, wearable computing. The early signs are positive and the industrial wheels are in motion. However, whether earphones truly become a disruptive new platform, or stop at being a useful accessory, could depend on whether we-the mobile computing researchers-deliver. If we do, tomorrow's earphones will run augmented reality via 3D sound, will have Alexa and Siri whisper just-in-time information, will track our motion and health, will make authentications seamless, and much more. The leap from today's earphones to "earables"could mimic the transformation we saw from basic-phones to smart phones. On the other hand, if we are unable to provide some of the disruptive building blocks, tomorrow's earphones may saturate in its capabilities. We believe this is an important juncture in time where the mobile computing research community has an opportunity to shape the future. This paper aims to discuss this landscape, including some challenges, opportunities, and applications.