In 1995, Iraqi dictator Saddam Hussein established his own Fedayeen corps, an irregular unit designed to protect the Ba'athist regime and Hussein himself. As of the 2003 invasion, they numbered 30,000 to 40,000 and their uniforms were more than a little unique, sporting an all-black combat uniform, black ski masks, and familiar-looking Darth Vader helmets.
Yes, Saddam's Fedayeen, Arabic for "Men of Sacrifice," wore enormous Darth Vader helmets. Their commander, Hussein's son Uday, was a huge Star Wars fan. The above picture is an actual example from the Imperial War Museum in Britain.
Other Middle Eastern personalities had their Fedayeen forces, notably Egyptian President Gamal Abdul Nasser and the Palestinian Liberation Organization, but neither of those had the Sci-fi panache of the Fedayeen Saddam. Founded in 1995, the irregular Iraqi guard unit was Saddam Hussein's personal militia.
Members were recruited into the Fedayeen Saddam as young as age 16. They received no specialty training or heavy weapons and were not members of the regular Iraqi military. So, as awesome as watching a fighting Darth Vader in "Rogue One" was, their Iraqi Doppelgängers were not so awesome.
In reality, they were mainly used to stop smuggling in Iraq, and then later became the smugglers, extortionists, torture, and whatever else the Husseins had them do. It was all good as long as they didn't shake down government officials.
Though U.S. military planners knew about the existence of the Fedayeen Saddam before the 2003 invasion, they weren't sure what they would be used for once the shooting started. The best estimate was as guerrilla fighters behind U.S. lines, which they generally did in urban areas. It was the Fedayeen Saddam who ambushed U.S. Marines in Nasiriyah under a flag of surrender in 2003.
Even after the regular army and Republican Guard forces crumbled away, the Fedayeen Saddam harassed U.S. troops through April 2003. Uday and Qusay famously found their end with a few members of the Fedayeen Saddam that same year.