Have you seen the documentary that came this year, think it's called "Last Of Us" - fungus can turn humans into zombies :)

But yeah, fungus directly controlling ant muscles, while it's brain is helpless is quite terrifying. Also terrifying is the raise of fungus infections in humans recorded in hospitals in India and UK in the recent years. If they do adapt to living in a warm human body we will have a major problem - fungus are killing more trees, bugs and reptiles than viruses and bacteria combined, the air in our cities is full of their spores.