Abu'l-Fadl al-Isfahani, also known as the Isfahani Mahdi was a young Persian man who in 931 BCE was declared to be "God incarnate" by Qarmatian leader Abū Tāhir Sulaymān. This new apocalyptic leader, however, caused great disruption by rejecting traditional aspects of Islam, and promoting ties to Zoroastrianism.
Abu Tahir's mother conspired to get rid of Abu'l-Fadl; she faked her death and sent a messenger to call the Mahdi to resurrect her. When he refused, he was exposed as being a normal human, and Abu Tahir's brother Said killed Abu'l-Fadl after the Mahdi had reigned for only eight days.
References
Abu'l-Fadl al-Isfahani Wikipedia(Text) CC BY-SA