Cordyceps - Intelligent design

Just so that you know what's really going on out there.

Though merely a cousin of the lowly toadstool, the Cordyceps fungus lives a life that could hardly be imagined by even the most creative science-fiction writer. Cordyceps lies quiescent on the forest floor, waiting for its unsuspecting insect prey to pass. When a bug wanders by, the fungus attaches itself to the insect exoskeleton. It then secretes a chemical that burns a hole in the insect's body armor. Next, Cordyceps inserts itself into the insect body and proceeds to devour all of the host's nonvital organs, all the while preventing the insect from dying of infection by secreting an antibiotic and a fungicide (as well as an insecticide to deter other insect predators). Once the nonvital organs are consumed, the fungus eats part of the insect brain, causing the insect to ascend to the top of a tall tree in the forest. At this point, Cordyceps devours the rest of the bug's brain, thereby killing the insect and causing the body to split open. At that point, the fungus can release its spores a hundred feet above the forest floor.

from Mark J Plotkin, Medicine Quest, quoted here.