Knoxx's Gold

 is a unique pistol manufactured by S&S Munitions. It usually drops as simply a high value gun, but it can also drop with any of the elemental effects, a scope, and various other improvements.

Examples are on the talk page.

Special Weapon Effects
Bling! - High resale value. Ability to improve drop quality is unconfirmed.

Drop Guide

 * Drops from General Knoxx.

Trivia

 * The name may be a reference to several James Bond releases.
 * The Man With The Golden Gun, in which the main villian has a golden gun.
 * Goldfinger, in which the titular character possesses many gold-plated items, including a golden pistol. Also, Fort Knox (see next point) is featured.
 * The name may simply be a reference to the United States Bullion Depository located near Fort Knox.