Entomophthora muscae, the "fly destroyer," is a fungus that infects the insect and zombifies. Then, at dusk, "the fly points its wings straight up and dies in a gruesome pose so that a fungus can ooze out and fire hundreds of reproductive spores."
"Oh, it's a nightmare for the flies," retired UC Riverside entomologist Brad Mullens told KQED's Deep Look. "If their little brains could comprehend it, they would live in fear."