When my sister and her husband went on a vacation in the island of Palawan, there was an incident when the rains came and their only refuge was a cave. It was a small cave but quite dark inside so they just stayed near the opening. While talking about the possibility of staying in that cave for the night since the rains looked menacing, they notices a snake slithering in the rocks. There was a also a big spider that looked harmful plus some other insects. When she told us that story, it was a neat lesson for us not to trust caves unless there is some locals or natives with us who knew the cave otherwise keep away from caves because more likely there are harmful creatures there.