Sunan an-Nasai 20464
In-book no 5728أَخْبَرَنَا سُوَيْدٌ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنْ جَرِيرٍ، عَنْ مُغِيرَةَ، عَنِ الشَّعْبِيِّ، قَالَ كَانَ عَلِيٌّ رضى الله عنه يَرْزُقُ النَّاسَ الطِّلاَءَ يَقَعُ فِيهِ الذُّبَابُ وَلاَ يَسْتَطِيعُ أَنْ يُخْرَجَ مِنْهُ .
It was narrated that Ash-Sha'bi said: "Ali, may Allah be pleased with him, used to give the people thickened grape juice into which flies would fall and not be able to get out again."