Zabo was an Iotian mobster employed by boss Jojo Krako. Zabo captured Captain James T. Kirk as he escaped from another mob boss Bela Okmyx. Later, when Kirk and Spock had captured Krako, Zabo would be rendered unconscious by a Vulcan nerve pinch. After waking up, he would lead a "hit" on Okmyx's gang in retaliation (only to be stopped by the USS Enterprise's phasers set on "stun" around a whole city block). (TOS: "A Piece of the Action")