It is a definition of fantasy, but it serves well to describe some complex cases of parasitism, those where fungi or other parasites attack insects and control their actions.

Horror. The most disturbing case is that of mushrooms such as the Ophiocordyceps unilateralis, a parasite of the ant Camponotus leonardi: when the spores penetrate the body of the insect they begin to colonize it, first feeding on soft tissues, then producing chemical compounds directed to the brain. The ant is forced to cling with the jaws to the nearest leaf. Here the Ophiocordyceps kills the specimen and finishes devouring it; when it is ready to reproduce, the fruiting bodies erupt from the ant's skull, as in the impressive video above.