The Super Elite is the large zombie with the machine gun. There is at least one on each level. There are also some in Horde mode. To do this more easily, play "Library Of Evil", "Tower Of Hellfire", "The Keep", or "Freight Train Of Fear". In "Library Of Evil", "The Keep", and "Freight Train Of Fear", you can find at least four of them. "Tower Of Hellfire" also has some, including one trapped under a tank (after the fight with the skeletons) that cannot shoot you and is an easy kill.