Hasn't that been ruled out by now though?

(Content warning: Zombie ant fungus details)

I read articles about that fungus and I believe for a long time it was assumed that the fungus rewires something inside the ant's brain that makes it want to climb to the top of a grass blade etc. - so it would "only" manipulate the high-level goals of the ant but not control the more complex and dynamic low-level operations (such as walking or navigating) directly.

However, a few months ago there was a paper about more detailed research on the molecular mechanisms the fungus uses for the takeover. Turns out, the former hypothesis was wrong and in fact it does control the ant's arms/legs directly. If that's true, then the fungus itself must somehow actively steer the ant towards the grass.