Musnad Ahmad 830:129

'Affan narrated to us, Hammad ibn Salamah narrated to us, 'Ali ibn Zayd informed us, from 'Abd al-Rahman ibn Abi Bakrah, from his father, that the Messenger of Allah (ﷺ) said: "The parents of the Dajjal will remain for thirty years without a child being born to them. Then a boy will be born to them who is the most harmful of things and the least beneficial. His eyes will sleep, but his heart will not sleep." Then the Messenger of Allah (ﷺ) described his father, saying: "His father is a tall man, lean of flesh, as if his nose is a beak. And his mother is a Faradakhiyyah woman, with long breasts." Abu Bakrah said: We heard of a newborn born among the Jews in Medina. I and al-Zubayr ibn al-'Awwam went until we entered upon his parents, and behold, the description of the Messenger of Allah (ﷺ) was in them. We said: "Do you have a child?" They said: "We remained for thirty years without a child being born to us. Then a one-eyed boy was born to us, the most harmful of things and the least beneficial. His eyes sleep, but his heart does not sleep." We left them, and behold, the boy was stretched out in a velvet blanket in the sun, making a murmuring sound. He said: "I uncovered his head, and he said: 'What did you say?' We said: 'Did you hear?' He said: 'Yes, my eyes sleep, but my heart does not sleep.'" Hammad said: "He is Ibn Sayyad."