Can't spell Fungeling without fun. Can I grow my own like a Chia Pet? What happens if I expose it to direct sunlight?
Here, we observe our subject finding a light source. A collapsed ceiling in the sewer structure. Unlike some fungus, Fungeling can endure bright sun conditions for a limited time. Some Fungelings will seek out sunlight and bask in the rays for a limited time. However, during peek hours, or when exposed to bright lights, Fungelings have shown a negative reaction. This particularly colorful subject, perhaps developed an appreciation for the smoggy light of Hoovesiana. Perhaps they could find better hunting conditions on the surface rather than in the dark tunnels. Then again, the surface comes with it's own risks making the decision not so black and white.
Report 18 on the Fungelings: The only way a Fungeling happens to occur is when a Changeling is infected with a currently unnamed mutant fungal infection. The origins of which seem to be similar to Cordyceps. This infection can occur post expiration of the original body but before full decay kicks in. A rough guess would be a week after the "host" expires without major damage to their internal organs. In a sense, one could "grow" a Fungeling or even infect themselves. However, the fungus will alter and attempt to fully control the brain and nervous system of the infected Changeling. In theory, killing the host if they were still alive. Research into the idea that a particularly strong willed subject could change this parasitic relationship into a symbiotic one is inconclusive. Sunlight does tend to stop their spread as the fungus only truly thrives in damp and dark areas, but they are not hindered on cloudy days or in the fog. Light shinned in either set of their eyes, particularly bright days, or even simple fires tends to cause them to avoid close proximity with it's source. Testing has also shown that the light from sun lamps cause them physical harm. Burns and boils occur similar to third degree burns. Lastly, fire seems to completely burn away the fungus, leaving hollow shells of the creatures behind. In short, burning the creatures to a crisp is the most effective way to stop their spread and having UV sunlamps set up around camps and security points will keep them at bay.
