He is a minor antagonist in Part III: Stardust Crusaders.
Gray Fly appears as an old man with a horseshoe hair style, and an imprint of a stag beetle on his tongue. He seems normal at first but is plain evil, taking up a modus operandi of killing his victims by cutting off their tongues with his Stand. His sadistic personality drives him to kill people just for fun. He has been known as a stand user who causes multiple accidents and kills people to steal their valuables. Kakyoin notes that Dio didn't need to use a spore to control him, so he was probably just hired to kill the Joestar group.
(Source: JoJo's Bizarre Encyclopedia)