Fester was Morticia's uncle.


Though Uncle Fester is a regular on the TV series, Charles Addams' prototype for Fester in the New Yorker cartoons was almost exclusively solitary, never shown indoors with the other family (except once as a painted portrait), and only once outdoors with the children (going fishing with dynamite).


With the start of the TV series, The New Yorker magazine stopped running any Addams-Family-themed cartoons from Charles Addams until just prior to his death in 1988, although a few familiar characters were allowed solitary appearances (the prototypes for Pugsley, Cousin...