Hadith 6205
Narrated Abu Huraira: Allah's Apostle said, "The most awful name in Allah's sight on the Day of Resurrection, will be (that of) a man calling himself Malik Al-Amlak (the king of kings).
Hadith 6206
Narrated Abu Huraira: The Prophet said, "The most awful (meanest) name in Allah's sight." Sufyan said more than once, "The most awful (meanest) name in Allah's sight is (that of) a man calling himself king of kings." Sufyan said, "Somebody else (i.e. other than Abu Az-Zinad, a sub-narrator) says: What is meant by 'The king of kings' is 'Shahan Shah.,"