Then Allah caused the earth to swallow him and his home. He had no group to help him against Allah, and he could not defend himself (28:81).
The people who had wished for his position the day before woke up with a different view. They said, in meaning, that Allah gives plentiful provision to whom He wills and restricts it, and that if Allah had not been gracious to them, He could have caused the earth to swallow them as well. They ended with the words that the disbelievers do not succeed (28:82).
Qarun is mentioned again briefly. In 29:39 he is named with Pharaoh and Haman as those who were arrogant in the land even though Musa came to them with clear proofs, and in 29:40 Allah says that some of those who were punished were those whom He caused the earth to swallow. In 40:23-24, Musa was sent with Allah's signs to Pharaoh, Haman and Qarun, and they said that he was a magician and a liar.