Jabir reported that there happened to pass before Allah's Apostle (ﷺ) an ass the face of which had been cauterised, whereupon he said:Allah has cursed one who has cauterised it (on the face).
وَحَدَّثَنِي سَلَمَةُ بْنُ شَبِيبٍ، حَدَّثَنَا الْحَسَنُ بْنُ أَعْيَنَ، حَدَّثَنَا مَعْقِلٌ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم مَرَّ عَلَيْهِ حِمَارٌ قَدْ وُسِمَ فِي وَجْهِهِ فَقَالَ " لَعَنَ اللَّهُ الَّذِي وَسَمَهُ " .
Muslim
The Book of Clothes and Adornment • Hadith 163