A major difference between Trial of the Crusader and Trial of the Grand Crusader is the Argent Crusade Tribute Chest. Upon entering the Coliseum in heroic mode you will be given 50 attempts to complete the instance. If the raid wipes 50 times, all undefeated bosses will despawn for the remainder of the lockout period. A minimum of 25 attempts remaining is required for the chest to appear after defeating Anub'arak. Higher amounts of remaining attempts will reward more and better items and achievements.