In Islamic eschatology, Masih ad-Dajjal is a one eyed false messiah:
Narrated 'Abdullah bin 'Umar:
Allah's Apostle said. "While I was sleeping, I saw myself (in a dream) performing Tawaf around the Ka'ba. Behold, I saw a reddish-white man with lank hair, and water was dropping from his head. I asked, "Who is this?' They replied, 'The son of Mary.' Then I turned my face to see another man with a huge body, red complexion and curly hair and blind in one eye. His eye looked like a protruding out grape. They said (to me), He is Ad-Dajjal." The Prophet added, "The man he resembled most is Ibn Qatan, a man from the tribe of Khuza'a. "
Source: Translation of Sahih Bukhari, Book 88: Afflictions and the End of the World, Volume 9, Number 242
His missing eye appears to be significant, as it betrays his true nature:
Narrated Anas:
The Prophet said, "No prophet was sent but that he warned his followers against the one-eyed liar (Ad-Dajjal). Beware! He is blind in one eye, and your Lord is not so, and there will be written between his (Ad-Dajjal's) eyes (the word) Kafir (i.e., disbeliever)." (This Hadith is also quoted by Abu Huraira and Ibn 'Abbas).
Source: Translation of Sahih Bukhari, Book 88: Afflictions and the End of the World, Volume 9, Number 245
Do we know how Masih ad-Dajjal ended up with such an obvious giveaway?