This is my first post (and hopefully there will be more) on the various denizens of the Conglomeration.

These are a couple ideas that have been floating around in my head for years, though I don't have any particular ideas for stories involving them. Mainly, I wanted to come up with some dangerous life forms not made of typical living matter. These particular organisms are not intelligent or even conscious, but imagine some charlatan selling you a "gem" that gradually drains your life. I figure some varieties of fool's gem might have a slight intoxicating effect on people. Jellylights have no such property, but people lured by their light in a dark forest would still fall victim.
The pentagonal shape of the fool's gems comes from real laws in mineralogy: crystals can show a variety of types of symmetry but cannot have 5-fold symmetry because regular pentagons will not form a regular repeating lattice. So it's slightly along the lines of "impossible geometries." 5-fold symmetry is possible with quasicrystals, but they have a non-repeating structure.