Surah Al-Qasas 28:31

وَأَنْ أَلْقِ عَصَاكَ ۖ فَلَمَّا رَءَاهَا تَهْتَزُّ كَأَنَّهَا جَآنٌّ وَلَّىٰ مُدْبِرًا وَلَمْ يُعَقِّبْ ۚ يَـٰمُوسَىٰٓ أَقْبِلْ وَلَا تَخَفْ ۖ إِنَّكَ مِنَ ٱلْـَٔامِنِينَ

And [he was told], "Throw down your staff." But when he saw it writhing as if it was a snake, he turned in flight and did not return. [Allāh said], "O Moses, approach and fear not. Indeed, you are of the secure.

Translation: Saheeh International

Tafsir

And ‘Throw down your staff’ and he threw it down. And when he saw it quivering moving as if it were a serpent jānn is a small snake so called because of the speed of its movement he turned his back to flee from it and did not look back in other words he did not return and so there called out the voice ‘O Moses! Come …

Excerpt from Tafsir al-Jalalayn, commentary on 28:31, via Quran.com. The reader has the full commentary and 9 more tafsirs.