This is not a great photo, but when I visit this odd pool I often forget to take a better one.
It is hidden well in a rough place, set in a cleft of jagged and vertically-oriented volcanic rock at the edge of a cliff that appears black from any distance.
There was a severe drought in this forest for a few years, yet this pool always had water in it when I stopped by.
When I first encountered it, the water was a milky yellow, yet live things were in there.