Black Mass Hysteria was created on 2012-02-14.
For a stellar black hole, yes. Mass cannot be created or destroyed. Generally a black hole will be less massive than the star from which it formed, as much of the star's mass gets blasted when the star dies in a supernova. A black hole can gain mass over time as matter falls into it.
The object swallowed by the black hole is destroyed; its mass is added to the mass of the black hole.
There is no "average" mass for black holes throughout the entire universe. Black holes range greatly in mass, depending on how they were formed, and how long they have existed if you take Hawking Radiation into account. Mass can be anywhere between a couple hundred protons, such as those created by cosmic rays striking Earth's atmosphere, or an enormous mass such as those in the center of almost every spiral galaxy.
The Mass at Bolsena was created in 1514.
Mass Distraction was created in 2002.
HYSTERIA IS MASS PANIC ---- Hysteria is a generic term for a condition with a non-organic cause.
The Aetiology of Hysteria was created in 1896.
Studies on Hysteria was created in 1895.
Love Hysteria was created in 1987.
Mas hysteria was created in 1980.
The Luxury of Hysteria was created in 2007.
The Blue Hysteria was created in 1996.
Livin' in Hysteria was created on 1991-03-01.
Full On... Mask Hysteria was created in 1992.
Black Mass - comics - was created in 1985.
Hysteria - Def Leppard song - was created in 1987.
Hysteria - Muse song - was created on 2003-12-01.