"Toxic fungus" refers to a type of fungi (a group of living organisms) that can be harmful or poisonous to humans or other organisms. It can cause various health problems if ingested, touched, or inhaled. Full definition
«Moose drool inhibits growth of toxic fungus.» (sciencedaily.com)
«Plants have evolved defense mechanisms to protect themselves, such as thorns, bitter - tasting berries, and in the case of certain types of grass, by harbouring toxic fungus deep within them that can be dangerous or even fatal for grazing animals,» says York U Biology Professor Dawn Bazely, who worked with University of Cambridge researcher Andrew Tanentzap and York U researcher Mark Vicari on the project. (sciencedaily.com)
That said, I think that we are so clueless about replicating even somewhat of a natural environment that makes us thrive that it's going to be hard to go to other places unless we figure out the microbial diversity and avoiding, say toxic fungus growing on your spaceship, because that'll sort of kill you as well as getting our lighting and even our EMF environment to replicate what we naturally had on Planet Earth. (blog.bulletproof.com)