Ophiocordyceps
This Camponotus worker ant has succumbed to an Ophiocordyceps fungus. The ant's death is peculiarly gruesome. In the early stages of infection the fungus takes partial control over the ant's brain, directing the ant to an area where the humidity is optimal for fungal growth. There, the ant bites down on a leaf vein, anchoring it in place. The fungus then kills the insect, consumes the tissues, and issues a fruiting body.
Jatun Sacha reserve, Napo, Ecuador