The miracle of blood’s precedent is that, one day the Holy Prophet (S) bled himself and gave the blood to Abu Saeed Khudri and asked him to bury it, but he drank it. His Eminence (S) asked: What did you do with the blood? He said: I drank it. His Eminence (S) said: I told you to bury it. He said: I have kept it in a safe vessel. His Eminence (S) said: Never do this again. After sometime, His Eminence (S) said: O Abu Saeed! Allah has made your blood and flesh unlawful on Hellfire because my blood and flesh has mixed up in it.
Hearing this, forty hypocrites laughed on His Eminence (S) and said: He thinks that on account of mixing his blood in the blood of Khudri he would be free from Hellfire. Though he is a liar and we consider his blood impure. The Holy Prophet (S) came to know this by divine revelation and he said: Allah will subject them to the punishment of blood and destroy them in it even though the Copts were not killed by the punishment of blood.
After sometime, their nose and molars started bleeding. Their blood was mixing in their food and water and they were eating like that. They suffered this for forty days and then perished.
Reference:Hayat Al-Qulub Vol. 2