Sources in the Palestinian naval police said at first that the body is an Israeli missile, due to the Intensive surveillance that was done by the Israeli drones in heavy presence aircraft over the beach, and because of its strong collision into the Sea.
However, the same sources did not rule out that it might be a shooting star or a meteor that fell from the sky, which happened in some cases before.
They added that further investigation are being conducted by experts to verify the nature of the body that was clearly seen by a number of eyewitnesses, fishermen and Marines." (source)