Looks natural. Seems this massive pillar-shaped stone has been lying on a watercourse for literally quite a long time and exposed to fast-moving water as evidenced by the typical shape of the erosion's effects-- smooth, stream-lined and the absence of angular or sharp edges. Presumably the top elongated dorsal fin-like projection was well above the water level during the active water-weathering phase and somehow would give one the idea that it must have been the remnant of the original size and configuration.
Possibly it could have served as a landmark or monument to a hidden treasure trove within a radius of tens or even hundreds of meters.
get a megacrane and have it brought over to the Philippine Navy Headquarters in Roxas Blvd, Manila to be displayed on the front lawn as a reminder that the Republic needs at least 1 submarine (even a WW II vintage) to spy on the encroaching Chinese in the West Philippine Sea.
--tabu
