According to Sony Alpha Rumors, Sony is planning a "lens camera" accessory for mobile devices. The lens camera features the same 1-Inch 20.2-megapixel Exmor R sensor and f/1.8 Carl Zeiss lens as the Sony RX100 II. Sony Alpha Rumors cites "two trusted sources" confirming the lens-camera-hybrid will have a built-in battery, NFC, and Wi-Fi. It'll be able to pair with (and mount onto) a number of smartphones, which will then act as a "live view" screen for the camera.
As incredibly unlikely as it seems, Sony Alpha Rumors is adamant that this is a real product that will be released soon. The site says the rumor has a "6" level of certainty — its rumor scale usually tops out at 5. The lens camera detailed above will apparently be part of a range of screenless cameras — a future product will feature a smaller sensor and larger zoom.