فَاَلْقٰىهَا فَاِذَا هِيَ حَيَّةٌ تَسْعٰى ( طه: ٢٠ )
Fa-alqaahaa fa -izaa hiya haiyatun tas'aa (Ṭāʾ Hāʾ 20:20)
So he threw it down, and thereupon it was a snake, moving swiftly. (Taha  : 20)
1 Mufti Taqi Usmani
So, he threw it down, and suddenly it was a snake, running around.