Surah Al-A'raf 7:107

فَأَلْقَىٰ عَصَاهُ فَإِذَا هِىَ ثُعْبَانٌ مُّبِينٌ

So he [i.e., Moses] threw his staff, and suddenly it was a serpent, manifest.

Translation: Saheeh International

Tafsir

Then he cast down his staff and lo! it was a serpent manifest for all to see an enormous snake.

Excerpt from Tafsir al-Jalalayn, commentary on 7:107, via Quran.com. The reader has the full commentary and 9 more tafsirs.