Fungus (like mushrooms) can be used in soils to feed on and clean up toxic chemicals / various neurotoxins.
From a press release by the Helmholtz Center for Environmental Research:
Because there is often a lot of traffic on the 'fungal highway’, the bacteria may come into close contact with one another, exchanging genetic material in the process. "It’s similar to the transmission of cold germs on a packed train," explains environmental microbiologist Dr. Lukas Y. Wick. "But unlike a cold, the new genes are usually an asset to the soil bacteria. They enable them to adapt better to different environmental conditions." Depending on the genes they receive through horizontal gene transfer, they may be able to adapt to new environmental conditions or access food sources which they were previously unable to exploit. For example, this might include the pollutants toluene or benzene contained in oil and gasoline, which to bacteria with the right genetic makeup are not only not harmful but actually very tasty food. So the passing on of this ability to other bacterial groups can be very advantageous in terms of the degradation of soil pollutants.
Image courtesy of: http://www.fungi.com/blog/items/the-petroleum-problem.html
"Meet the Neurotoxins"