Musnad Ahmad 1153:2113

'Abd al-Samad narrated to us, Zayd—meaning Ibn Murrah Abu al-Mu'alla—narrated to us, from al-Hasan, from 'A'ishah: "The Messenger of Allah (ﷺ) permitted the killing of animals while a man is in the state of ihram: that he should kill the snake, the scorpion, the vicious dog, the pied crow, the kite, and the mouse." A scorpion stung the Messenger of Allah (ﷺ), so he ordered its killing while he was in the state of ihram.