This was the first stage of a SpaceX Falcon 9R after launching the ORBCOMM satellite, re-entering the atmosphere, and soft-landing on the ocean.
Future launches will attempt a soft-landing on the ground, something that, if successful, can further decrease the cost of launching payloads into orbit. There will be no need to use a new first stage booster for every launch, something that can dramatically reduce the costs and turnaround times associated with space flight.
(H/T NextBigFuture)