Lavacicles (lava stalactites) in a lava tube cave in the Lava Beds National Monument (California).
Lavacicles look like melted chocolate!
Some white carbonate deposits (speleothems) was also formed when water dripped from the lavacicles formations.
For more info about Lavacycles, read: en.wikipedia.org/wiki/Stalactite#Lava_stalactites.
For more info about this place, read en.wikipedia.org/wiki/Lava_Beds_National_Monument.
Lava beds and geothermal features in the Pacific North-West.