Al-Masih ad-Dajjal
al-Dajjal (Arabic: الدّجّال, al-dajjāl) ("The Deceiver/impostor") is an evil figure in Islamic eschatology, who will appear before Yawm al-Qiyamah (Resurrection Day). He is also known as the Antichrist in Christianity. It is rather interesting to note the similarities between "Dajjal" and "Devil", when both comparatively spoken properly.
"Dajjal" is a common Arabic word, used in the sense of "false prophet". But "Al-Dajjal", with the definite article, refers to "The Impostor", a specific end-of time deceiver. It is worthy to note that the term Al-Masih Ad-Dajjal (Arabic for "The False Messiah") is a literal translation of the Syriac term "Meshiha Deghala", which had been in the common vocabulary of the Middle East for more than 400 years prior to the Qur'an via the Peshitta (which uses that term instead of the Greek "antichristos").
Alternative theory
In his book Antichrist: Islam's Awaited Messiah (ISBN 1414104405), Joel Richardson makes the argument that the Dajjal is in reality the Second Coming of Jesus Christ and that the reason the Dajjal is described as an evil figure in Islam is due to deception on the part of Satan.
This argument however ignores both sayings of the Prophet Muhammad (s.a.w.s.) that indicate both the Mahdi (s.a.) and Jesus (s.a.) fight side by side, and, book of Zechariah's (Zach 3, 4) specific mention of [Joshua] crowned alongside another elect of God (called the Branch) as the two anointed ones(Zach 4.14). Thus, both Muslim and Judeo-Christian scripture foretell of 2 anointed ones, one as Priest and the other as King.