فَكُبْكِبُوا۟ فِيهَا هُمْ وَٱلْغَاوُۥنَ
Fakubkiboo feehaa hum walghaawoon
and then they will all be hurled into Hell, together with those that misled them,
Then they will be hurled into it, they and those who led them astray,
Kubkibū is a doubled form, the consonants of the verb for toppling said twice over, so the word itself tumbles as it describes tumbling. The same participle stood a few lines earlier for people who had strayed, and it is taken both ways here, of the misled and of the ones who misled them. Either way the two arrive together, and the quarrel that follows is between them.