Abū al-Tufayl, who was asked, “Have you seen the Messenger of Allah ﷺ?”
He replied, “Yes.”
Someone then said, “Did you speak with him?”
He answered, “No. I only saw him go to such-and-such a place, accompanied by ʿAbd Allāh ibn Masʿūd and a group of his Companions, until he came to a spacious house.
He said, ‘Open this door.’ They opened it, and the Messenger of Allah ﷺ entered; I entered with him. There was a quilt lying in the middle of the room.
He said, ‘Lift up this quilt.’ They lifted it, and beneath it was a one-eyed boy.
He said, ‘Stand up, boy.’ The boy stood.
He said, ‘Boy, do you testify that I am the Messenger of Allah?’
The boy replied, ‘I testify that I am the Messenger of Allah.’
He repeated, ‘Do you testify that I am the Messenger of Allah?’
The boy replied, ‘I testify that I am the Messenger of Allah.’
The Messenger of Allah ﷺ then said, ‘Seek refuge with Allah from the evil of this one,’ twice. (1)

What is meant here is that Ibn Ṣayyād is certainly not the Dajjāl who will appear at the end of time. The ḥadīth of Fāṭimah bint Qays al-Fihrīyyah settles the matter definitively—and Allah knows best.

The ḥadīth of Fāṭimah bint Qays concerning the Dajjāl:
Muslim relates: ʿAbd al-Wārith ibn ʿAbd al-Ṣamad ibn ʿAbd al-Wārith and Ḥajjāj ibn al-Shāʿir both narrated to us from ʿAbd al-Ṣamad (the wording is that of ʿAbd al-Wārith ibn ʿAbd al-Ṣamad). He said: My father related to me from my grandfather, from al-Ḥusayn ibn Dhakwān; Ibn Buraydah narrated to us; ʿĀmir ibn Sharāḥīl al-Shaʿbī—of the tribe of Hamdān—told me that he asked Fāṭimah bint Qays, the sister of al-Ḍaḥḥāk ibn Qays, who was among the earliest Emigrants.
He said, “Tell me a report you heard from the Messenger of Allah ﷺ and attribute it to no one but him.”
She replied, “If you wish, I will do so.”
He said, “Indeed, do so.”
She said, “I married the son of al-Mughīrah, who was one of the finest young men of Quraysh in those days, and he was struck down in the first campaign fought alongside the Messenger of Allah ﷺ.
“When my waiting period (ʿidda) was over (2), ʿAbd al-Raḥmān ibn ʿAwf, together with several of the Companions of Muhammad ﷺ, proposed to me, and the Messenger of Allah ﷺ also proposed on behalf of his freedman Usāmah ibn Zayd.
“I had been informed that the Messenger of Allah ﷺ had said, ‘Whoever loves me, let him love Usāmah.’
“So when the Messenger of Allah ﷺ spoke to me I said, ‘My affair lies in your hands; marry me to whomever you wish.’
“He said, ‘Move in with Umm Sharīk.’ Umm Sharīk was a wealthy woman from the Anṣār who spent freely in the path of Allah, and many guests stayed with her.
“I said, ‘I will do so.’
“He said, ‘Do not do that. Umm Sharīk is a woman visited by many guests, and I dislike that your head-cover should slip or your garment rise and expose your legs, and the people see of you what you would detest. Rather, move in with your cousin ʿAbd Allāh ibn ʿAmr ibn Umm Maktūm.’
“He was a man of Banū Fihr—the branch of Quraysh to which I also belong—so I moved in with him.
“When my waiting period ended, I heard the caller of the Messenger of Allah ﷺ announcing, ‘The congregational prayer!’
“I came out to the mosque and prayed behind the Messenger of Allah ﷺ, standing among the women who formed the last rows behind the men. When the Messenger of Allah ﷺ had completed his prayer ….”