I didnt read the article, but I think I already heard of this somehere.
So this specific mushroom, or fungus, when mature, releaces this giant cloud of spores to reproduce. The spores can land on anything: trees, grass, ants, anything. Eventually, one spore will land on an ant. This is where is gets weird.
The spore has no sentinence, it just grows. However, it responds to it's environment, but only at the cellular level (It does not have a brain). So it will grow on an ant just like it would grow on a beetle, or a tree, etc, but differently, because the ant's carapace will slow the root gorwth.
Most mushrooms carry at least some kind of toxin, except the mushrooms that we eat. I am not sure, but this mushroom possibly carries a neurotoxin which ends up poisoning the ant.
The ant, still alive is carried out of the hive by fellow worker ants (they have seen this before). There, the ant, being poisoned, climbs up as high as he can. I am still unsure why. All I know is, high places are great for spore dispersal.
Soon, the ant dies, and the fungus decomposes the ant's dead body. It grows and grows until it reaches maturity and releaces a deadly cloud of spores which seek new hosts.
If the fungus was allowed to grow inside the hive, it's spores would eventually consume the entire hive. Ants are smarter than they look.
I hope that answers your question.