What the heck is this brown stuff the dentist put on my gum after surgery?

I recently had all four of my wisdom teeth out. After about a week, I went back for a check-up and the dentist put this disgusting brown moss-like stuff in one of the gums to help it heal and prevent infection, I guess. It was really gross, and I was just wondering if anyone else has had this experience?

I think that stuff is cloves or some herbal type remedy. They usually do that if you have lost your blood clot, which would protect you from getting “dry socket” That nasty clove stuff is supposed to act like a pain reliever. Look up “dry socket” and they call that ‘packing’.