It is the premise of THE LAST OF US on the Playstation 3 console.
Disgusting! Interesting to contemplate just what is possible. These and similar parasites tend to focus on large successful lifeforms that are prodigious and social ... like humans, who would be ideal.
Most to worry about would be government labs wondering about the value of studying and weaponizing this fungus for use on enemy populations - or their own. Read in the article above how they are in wide use in biomedicine right now in immunosuppression and other cellular level controllers. All they need to do is to start to play around with it genetically.
More reasons to take garlic every day.