The rite "black" witches were said to hold to parody the Catholic mass. They often said segments of a normal mass backward, used humans for altars, and generally insulted and perverted Catholicism.
A: Somebody said some witches held a black mass the other night.
B: That's shit, it never happens anymore.
B: That's shit, it never happens anymore.
by Matt Miller July 26, 2005
A black cloud of smoke which moves around at will, generally in old Victorian era homes and forests and eerie places. Think "The Monster" from the TV show Lost.
"I went up to the hallway... I saw a black mass. I tell you what, I was scared. I was frightened out of my wits."
by Jacob Leary September 26, 2008