Did you know the person who propagated the idea of Mahdi and his army through fake hear say, came out claiming to be Mahdi centuries ago?
"Abu Muslim was a genius and a highly skilled person in the art of intrigue. He was born in Isfahan (Persia) and bred in Kufa (Iraq). Ibrahim son of Muhammad Abbas, having realised his intellectual capacity, put him in charge of the propaganda machinery. Abu Muslim made Khurasan his centre and without giving publicity to any one person, successfully carried out the campaign against Bani Omayya. Incidentally, in those days the idea of Im’am Mehsi (the idea of return of an Im’am from hiding), was in vogue. Anu Muslim gave publicity to the fact that Im’am Mehdi would soon be coming from the Khurasan side and that his army would be clad in black uniforms and its flag would also be black. When the propaganda reached its pitch, he himself came out of Khurasan with a black army and black flag, attacked Bani Omayya and defeated them. The Abbasids, after they took the reigns of power, became apprehensive of Abu Muslim’s intellect, intriguing qualities and influence, and killed him."