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What’s building this weird “mystery fence” in the Amazon?

Spiders? Fungi? Faeries?
It began when a Georgia Tech doctoral student named Troy Alexander noticed a strange tiny structure stuck to the underside of a tent Alexander was sheltering under while working at a research center in Peru. At the time, he thought that a moth had started building itself a cocoon, but had been eaten before it could complete its work. He snapped a few pictures, but neither the research center's entomologist nor a Reddit group dedicated to identifying insects had ever seen anything like it.
 
Soon, Alexander started spotting these tiny structures everywhere. They have no doubt always been there, but no one had ever noticed them. They are tiny, about two inches across, and found on tree trunks and the undersides of leaves. And now that Alexander was looking for them, he spotted several more.
 
The central part of the structure is shaped a bit like a white Hershey's Kiss. It has a long spire which seems to be attached to the top of the surrounding fence. The fence is pretty amazing: it looks like a tiny circular picket fence, with about four dozen vertical "fence posts" lashed together with strands of silk.
 
No one has yet been able to identify the creature that is making these dainty little fairy rings. Some Redditors have suggested that it might be the work of a previously unknown species of spider. Although most spiders spin silk threads out of their spinnerets, some species have a cribellum instead, which basically pushes the silk through a fine mesh. Instead of spinning a web, these spiders comb out the fibers into something more like a woolly wad, which entangles the prey insects (instead of trapping them in the sticky fibers of a web).
 
Many people have speculated that the central structure is an egg sac, and that the fence is a way of keeping out unwanted pests. If so, isn't it fascinating that humans and spiders would come to the exact same architectural solution to the problem of interlopers?
 
Another possibility is that it is the work of a fungus. Some fungal growth stages can be truly bizarre, and the rain forests of the Amazon are prime territory for undiscovered fungi.
 
Unfortunately, no samples were collected at the time. It wasn't until much later that Alexander realized the uniqueness of his discovery. Teams will be returning to the Amazon in the next research season to explore, catalog, and investigate these structures further.