al-Jassasa

The Jassasa is a great creature that appears in the report of Tamim al-Dari, as transmitted by al-Masudi. ²

Tamim relates that he boarded the sea with a group of his cousins, and that the ship went astray with them and cast them onto an island. They saw a great creature that had spread out its hair, and it said that it was the Jassasa, and that it would come out at the end of time. ²

It guided them to a palace, in which was a man chained with iron to a pillar. He addressed them and said that he was the Dajjal, and he told them a number of prophecies, and that he would not enter the city of the Prophet ﷺ. ²

The only source given here is al-Masudi's report. It needs a further source.