Tafseer Ibn Kathir of THAAHAA [66]

قَالَ بَلْ أَلْقُوا فَإِذَا حِبَالُهُمْ وَعِصِيُّهُمْ يُخَيَّلُ إِلَيْهِ مِن سِحْرِهِمْ أَنَّهَا تَسْعَى

He said, "Rather, you throw." And suddenly their ropes and staffs seemed to him from their magic that they were moving [like snakes].