Morticia and the Psychiatrist - S1-E2
Continuity mistake: When Morticia is watching Gomez and the trains, at the second of the collision and explosion, it's a re-use of the shot when Mr. Hilliard is there, as in just a split second, you can see him, then there's Morticia again.
The Addams Family and the Spaceman - S1-E27
Other mistake: In this episode, the radio announcer said that the reported spacecraft was seen over the Cemetery Ridge District, and Morticia said "That's our area." However, in "Cousin It Visits The Addams Family" (S1: Ep 20) they are supposedly in the Greenbriar Woodlawn District.
The Addams Family Tree - S1-E5
Audio problem: With Morticia in his arms, he says "And I dropped you...only once." If you watch his profile, you can see that his face never moves. Hard to believe especially when you know he had an animated face.
Christmas with the Addams Family - S2-E15
Other mistake: As Morticia starts to play the flute, Gomez appears to have been filmed backwards, his hair and suit is reversed.
Christmas with the Addams Family - S2-E15
Revealing mistake: When Morticia is playing the flute, the strings that operate the basket lid and rope are visible.
The Addams Family Goes to School - S1-E1
Audio problem: When Wednesday comes into the house crying her mouth isn't moving.
The Addams Family Goes to School - S1-E1
Audio problem: After Gomez suggests the rack for a stretch, he rings for Lurch. You hear Lurch say "You rang?", but his lips don't move.
Cousin Itt Visits the Addams Family - S1-E20
Revealing mistake: In the wide shot of the family watching Cousin Itt perform magic tricks, you can see Felix Silla's legs as they probably didn't intend for the whole character to be in frame.
The Great Treasure Hunt - S2-E19
Revealing mistake: When Fester gives the anchor to Morticia, she drops it, and it bounces back up. When she lays it down, the wire used to achieve the gag is easily seen.
Visible crew/equipment: Whenever Thing comes out of his little places you can see a wire that is used to open up the little hiding place.
Continuity mistake: While playing chess, and when Pugsley calls him, Thing is a left hand. When he comes up in the garden area, he's a right hand.
Uncle Fester's Illness - S1-E18
Continuity mistake: When we see Wednesday playing a game with Thing she is missing two front teeth. Later when the doctor comes to check on Fester she is only missing one front tooth.
Continuity mistake: After the doorbell knob retracts into the frame, the door starts to open. After the angle change, the door starts to open again.
The Addams Family Goes to School - S1-E1
Continuity mistake: When Wednesday is first holding her doll, the buttons are facing forward. A second later, it's backwards.
Other mistake: As Kitty comes down the stairs, Hilliard screams, and Kitty goes back up. It's obvious the film was run backwards.
Answer: Basically from what I understand, they stuck the innards of a small flashlight into the base of the bulb and put a little switch on it. When he put it in his mouth and bit down, his teeth would hit the switch, which would turn on the flashlight and made the bulb light up.
TedStixon