Used to express irritation or ironic resignation when an additional, unexpected person or problem appears, making an already difficult or crowded situation worse or more complicated.
An exclamation equivalent to 'as if things weren't bad enough, now this' or 'just what we needed' used ironically.
Examples:
ES: Porque ahora resulta que éramos pocos y parió la abuela.
EN: One dancer in the house is enough, because I already have the Bolshoi.