Seeing them in a dream is hardship and torment, because of His saying, the Exalted:
وَإِذَا غَشِيَهُم مَّوْجٌ كَٱلظُّلَلِ دَعَوُا۟ ٱللَّهَ مُخْلِصِينَ لَهُ ٱلدِّينَ فَلَمَّا نَجَّىٰهُمْ إِلَى ٱلْبَرِّ فَمِنْهُم مُّقْتَصِدٌ ۚ وَمَا يَجْحَدُ بِـَٔايَـٰتِنَآ إِلَّا كُلُّ خَتَّارٍ كَفُورٍ
“And when waves come over them like canopies, they supplicate Allāh, sincere to Him in religion [i.e., faith]. But when He delivers them to the land, there are [some] of them who are moderate [in faith]. And none rejects Our signs except everyone treacherous and ungrateful.”
Quran 31:32 · Saheeh International
And His saying, the Exalted:
قَالَ سَـَٔاوِىٓ إِلَىٰ جَبَلٍ يَعْصِمُنِى مِنَ ٱلْمَآءِ ۚ قَالَ لَا عَاصِمَ ٱلْيَوْمَ مِنْ أَمْرِ ٱللَّهِ إِلَّا مَن رَّحِمَ ۚ وَحَالَ بَيْنَهُمَا ٱلْمَوْجُ فَكَانَ مِنَ ٱلْمُغْرَقِينَ
“[But] he said, "I will take refuge on a mountain to protect me from the water." [Noah] said, "There is no protector today from the decree of Allāh, except for whom He gives mercy." And the waves came between them, and he was among the drowned.”
Quran 11:43 · Saheeh International