Jabir. Samura reported
I saw the seal on his back as if it were a pigeon's egg.
This hadith has been narrated on the authority of Simak with the same chain of transmitters.
As-Sa'ib b. Yazid reported
My mother's sister took me to Allah's Messenger (ﷺ) and said: Allah's Messenger, here is the son of my sister and he is ailing. He touched my head and invoked blessings upon me. He then performed ablution and I drank the water left from his ablution; then I stood behind him and I saw the seal between his shoulders.
Abdullah b. Sarjis reported
I saw Allah's Apostle (ﷺ) and ate with him bread and meat, or he said Tharid (bread soaked in soup). I said to him: Did Allah's Apostle (ﷺ) seek forgiveness for you? He said: Yes, and for you, and he then recited this verse:" Ask forgiveness for thy sin and for the believing men and believing women" (xlvii. 19). I then went after him and saw the Seal of Prophethood between his shoulders on the left side of his shoulder having spots on it like moles.