Final Trump
The Final Trump was an imaginary sabacc hand. On his way to the Battle of ThonBoka, one of the most dangerous situations of his life, Lando Calrissian had a nightmare in which he was playing sabacc against a mysterious, gray opponent, which was meant to be Rokur Gepta.
His opponent's hand was the Final Trump, which represented an automatic win for whoever held it, a good representation of Lando's fears that he would not survive the coming battle no matter how cunning he was.