http://www.digitaljournal.com/article/84441

Fungus that mind-controls ants to assist in spreading

Posted Jan 3, 2007 by Thespian

http://www.boingboing.net/2007/01/03/video_of_fungus_that.html

Driven on and on by the still-growing fungus, the ant finally achieves a seemingly prescribed height whereupon, utterly spent, it impales the plant with its mandibles and, thus affixed, waits to die.
This is freaky. The fungus infects a species of ant, starts growing in its brain, forcing behavioral changes which make the ant climb trees and vines to get to a hight where the fungus grows. The fungus continues to grow, consuming the ant's body, and eventually producing a spore antenna out the ant's head to rain spores back down on the ground to start the cycle all over.
Sci-Fi and horror writers have nothing on on some of the wacky stuff nature pulls in its arms race between creatures.