Morticia and the Psychiatrist - S1-E2
Visible crew/equipment: When Uncle Fester climbs down the tree (after observing Pugsley interact with the shrink, a shadow of the moving dolly mic is visible as it moves backward. (00:22:35)
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.
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