Surah Al-Muddaththir 74:50
كَأَنَّهُمْ حُمُرٌ مُّسْتَنفِرَةٌ
As if they were alarmed donkeys.
Translation: Saheeh International
Tafsir
as if they were wild asses
Excerpt from Tafsir al-Jalalayn, commentary on 74:50, via Quran.com. The reader has the full commentary and 9 more tafsirs.