وَتَكُونُ الْجِبَالُ كَالْعِهْنِ الْمَنْفُوشِ
And the mountains will be like carded wool. (101:5)
Al-jibālu is the subject of takūnu; the comparative prepositional phrase functions as its predicate. Al-ʿihn denotes wool, often understood as colored wool, and al-manfūsh depicts it as fluffed or carded. The simile overturns the familiar solidity of mountains.
The wāw in wa-takūnu joins two connected scenes. Though the subjects differ—people and mountains—their common relation to the same catastrophic day provides the semantic link (jāmiʿ).