Question about background at Leafre

ok in last month i was doing quest to get silver mane so i go hunt some pads at cornian map, and i saw something strange, this rock of image was glowing like statues at gpq (when you drop spear), unfortunately i took few time to ss and effect vanished >_<, i tried look for effect again but nothing, so anyone know/saw that effect before and know what that means ? or is just a random map effect?

ss of stone (without effect =[) - name of map is The Hidden Dragon Tomb II

 Spoiler