When someone fails terribly this word/phrase is the only way of compensating for their act disregarding any other words as no other words can come to mind other than this word/phrase. (Warning only to be used if a severe act of failure has been committed).
If this word/phrase (Fail Blob Chaar) were to be defined in a simplistic approach... if someone was a complete idiot and ruined the most easy of tasks. Any person knowing this worthy phrase would insult them using this phrase that will shine through the years passing on as my legacy.