Musnad Ahmad 32:317

Yahya narrated to us, from Humayd, who said: "A man peered at the Prophet, peace and blessings of Allah be upon him, through a gap. The Messenger of Allah, peace and blessings of Allah be upon him, aimed an arrow-head at him until he drew his head back." Yahya said: I said, "Who narrated this to you, O Abu Ubaydah?"—meaning Humayd. He said: "Anas."