'Mob Wives' Star Angela 'Big Ang' Raiola -- The Case of The Mysterious Mural

"Mob Wives" Star Angela "Big Ang" Raiola is a real piece of work -- the reality TV star's mug has been plastered all over NYC lately on giant mural scenes, but no one knew why ... until now.

TMZ has learned the the mob wife's been immortalized in caricature as part of a promotional campaign for BA's VH1 spin-off show called, you guessed it ... "Big Ang."

Sources close to the production of Ang's new show tell us, the network and a marketing firm hired real deal NYC street artists to design and paint the ginormous murals around the city purely to promote the summer series.