The Playstation Camera.
But for now, it's just there to do cool things like log you in by facial recognition, know who's holding which controller, voice navigation, video feed for streaming, & the free Playroom tech demo, which shows off a lot of cool potential for the camera.
However, again, there's not much talk on how games will utilize it. Sony has said that it's able to recognize depth similar to Kinect, but hasn't really shown that off at all. Recently, Sony briefly mentioned that their research & development labs are looking into eye tracking with the camera, but didn't say more than that. Overall, they've been very quiet about the camera, which either means that they have lots more to announce for it in the future, or it's potentially doomed.
The problem here is that they didn't bundle it in with every PS4 like the Xbox One did with the new Kinect, and that will mean that there will be less developers willing to support the peripheral, similar to what happened with PlayStation Move.
At the very least, I suspect that Sony will have a handful of first party titles that will utilize the camera in cool ways, similar to how several 1st party Sony games supported the Move, or required it. But until those and more come, there just isn't much known about the camera and what games will use it...