Hazrat Muhammad SAW said that Ad-Dajjal aka anti-Christ would be the biggest fitna on the planet. It is because he will be capable of bringing life and death to the people but by the will of Allah. Moreover, he will be the strongest being on Earth and there will be no other to compete him.
The Appearance of Ad-Dajjal (anti-Messiah)
Ad-Dajjal would not be some alien or jinn, he would be a simple young man with cropped, twisted hair (like an afro). He would be short, fat with white complexion. The letters k.f.r (Kaafir) would be engraved on his forehead which will reflect that he is Dajjal and Kaafir. Only Muslims, not munafiq but true Muslims would be able to read that word (both literate and illiterate). He would claim that he is Allah, but remember Allah is not one-eyed whereas Dajjal would be blind from his right eye which would look like a bulging out grape.
Dajjal (anti-Christ) would have unusual powers. He would have power to walk on the earth with lightning speed. He would be powerful enough to turn houses into decays and decays into treasures. He would declare himself a God and invite people and ask them to accept him as a God. The people with less faith would accept him and respond to him.
He would then give those peoples prosperity and opulence. Their crops would be healthy and their pasturing animals would come to them with very high humps, as distended flanks and udders full of milk.
He would then invite more people but they will refuse him so he would go away, but they would have dryness and their wealth will also be gone.
He would have both a Paradise and Hell. But his Paradise and Hell would be reversed. If a person would choose his hell between his paradise and hell then that person would go in Jannah and vice versa.
Interestingly, most of his followers would be Jews and women. Why Women? Because they are weak-hearted, sympathize quickly and get under pressure easily. Both of them would be impressed by his false miracles. The followers of Ad-Dajjal (anti-Messiah) would also be ignorant masses, back wings, and hypocrites.
He would emerge between Iraq and Syria and would spread mischief to both right and left. His reign would be of only 40 days; one day would be like a year, other day like a month, next day like a week and the rest of them would be like simple our days. Thus, he would stay for 1 year and 3 months on earth as mischief-maker. He would come and go anywhere in the world except from one place and that is Mecca and Medina.
People would think that they can hide from Dajjal or anti-Messiah by entering into Mecca and Madina. But they should know that medina would be shaken thrice during that time, because of which seventy thousand munafiqs (hypocrites) would run out from it. Hence, in order to stay in Medina, one should have strong faith.
Dajjal: anti-Christ would emerge from Asbahan in Kharrasaan which is somewhere in Persia/Central Asia. Presently, mostly Jews occupy that place. Therefore it is believed that he would emerge in between Jews and his most of followers will also be Jews.