The brown stuff is a mature slime mold and I believe the tiny insect is a Collembola (springtail). About 2.5mm long not counting headgear.
I believe these were built by a potter wasp and contained eggs. The wasp probably provisioned them with insects that it paralyzed and stuffed into the chambers before sealing them. If you want to see more of the amazing egg cases and nests built by arthropods there is a special section on this site under "Insect eggs."
Opiliones sometimes do this.
