A puppeteer parasite is a parasitic creature capable of commandeering control of it's host organism.
Puppeteer Parasites in Real Life
Several species of parasitic organisms can influence creatures. This includes fungus and a few species of Flukes. Their control is generally limited, as both host and parasite have limited processing power. The final results of most of these infections is the positioning of the victim in a place that will facilitate the reproduction of the parasite infecting them. In insects, the fungus tends to push the victim into place where it's spores can easily infect other insects. Cordyceps fungus can be so invasive as to be able to wipe out an entire ant colony in a matter of days.