In a plot that seems to be hijacked straight from B-grade horror flicks, the tropical fungus Ophiocordyceps unilateralis apparently uses the unsuspecting ants known as Camponotus leonardi in a remarkable fashion, compelling them to move to prime fungus habitat before killing and using the hapless creatures as launchpads for future fungus spores.

Upon infestation, the ant promptly leaves its normal treetop home, climbing down in search of a location suitable for the fungus to grow. According to research soon to be published in Chicago's The American Naturalist, this location is chosen by the infected ants with remarkable precision: almost all end up 25 centimeters above ground on the North side of a plant, in a spot with 95% humidity and temperatures between 20 and 30 degrees Celsius. This kind of precision is clearly advantageous to the fungus -- infected ants that were moved to other types of locations always failed to develop spores for their mind-controlling hosts.

Those ants left in their chosen positions, however, proceeded to bite down on the underside of a leaf and die, with fungal threads emerging from their heads after only a few days, followed by spore-carrying perithecial plates (marked "P" in photo) within a week.

Read more about the horror at http://www.scientificamerican.com/article.cfm?id=fungus-makes-zombie-ants