Antioch is Fatz Geronimo's pet spider that would descend from the ceiling above the stage (between Fatz and Dook LaRue) on center stage of The Rock-afire Explosion. Antioch took his name from the location of the first ShowBiz Pizza Place, in Antioch Center in Kansas City, Missouri.
During Concept Unification, which took place at nearly all of the ShowBiz Pizza locations between 1990 and 1992, Antioch was removed, and his computer and air lines were reused for the Wink above center stage. After this, his animatronic was likely destroyed, put into storage, or sold to multiple collectors.
It should be noted, however, that on the Prototype Concept Unification Stage, his animatronic was removed completely, along with the other props and prop characters. This was in order for a traveling Mr. Munch animatronic.