Tombstone is a town in Arizona famous for the Old West Gunfight at the OK Corral.
Morticia Addams suggests it would be a fun place to vacation. While on a vacation out West, The Addams Family are mistaken for cattle rustlers from Tombstone. One Halloween, Gomez Addams has to leave the family festivities to attend a lodge meeting there.
The Addams Family original series episode:
The Addams Family 1973 animated episode:
The television special: