Can a battery go bad instantly?

my battery went bad with out warning take it to a auto parts store for a free check they will put a load on it to see if its okay

It happened to me once in my brief 60 years on this earth. The typical 12 volt lead acid car battery is made up of 6 cells, 2 volts each which are connected together internally by lead straps. Rarely strap connections or the straps themselves will fail resulting a 0 volt condition. This would hold true for other internal connections within the battery also ofcourse but this is the one I hear of most. Generally not something to worry about. Practically all battery failure occurs over time and gives plenty of warning in the form of slow cranking.