Humbug Not to Be Spoken Here - S4-E16
Other mistake: In the previous episode, I've Got Your Nanny Right Here, Samantha tells Darrin "nobody travels by broom stick anymore. It's obsolete." She takes Mr. Mortimore to North Pole by broomstick.
Samantha's Da Vinci Dilemma - S4-E17
Revealing mistake: When Leonardo is going through the revolving door his arm/elbow goes through the frame where glass should be.
Hippie, Hippie, Hooray - S4-E21
Plot hole: Why would Serena need Samantha to zap her out of jail? Serena is a witch and very tricky.
Hippie, Hippie, Hooray - S4-E21
Continuity mistake: In season 4 episode 10 (That Was No Chick, That Was My Wife) Louise and Larry met Serena when Sam was explaining why she was home and not Chicago. Then in this episode neither Larry nor Louise know about Serena.
How Green Was My Grass - S4-E24
Continuity mistake: Before this episode (and after as well) Darrin and Samantha give their address as 1164 Morning Glory Circle, however in this episode, when Darrin slams the door, the '9' in 192 on their address spins around to make 162, hence the angry neighbor at 162 saying that his grass was installed at the Stevens' by mistake.
Audio problem: Tabitha is heard saying "Okay," but her lips don't move. (00:03:45)
Continuity mistake: The amount of toys on the floor suddenly increases as Michael's mother heads to the front door. (00:06:45)
Character mistake: Samantha calls Darrin's mother "Mother Stephens" throughout episode. In most episodes, she is "Mrs. Stephens." I can't find any other episode where she is "Mother Stephens".
Visible crew/equipment: Right after Samantha, Darrin and Tabitha pop out of the living room, the shadow of what looks like a camera rolling backwards can be seen on the floor. (00:21:55)
Continuity mistake: Uncle Arthur telling Darrin that a charm that he is being given is going to protect him. However, his pistol has managed to go right through Darrin and into the wall in the background. Then, the next frame, the shots are on his pocket. (00:10:22 - 00:11:00)
Samantha's Wedding Present - S5-E1
Continuity mistake: When Darrin is on the table and growing he is wearing a green suit, when he is full size, he is wearing a blue suit.
Samantha's Wedding Present - S5-E1
Other mistake: When Darrin is first shrunk we see that his clothes are unaffected by Endora's spell (they don't shrink). So, when he was popped back to normal heights, his clothes shouldn't be affected, and he would burst out of them. We already know his suit changed colors.
Samantha Goes South for a Spell - S5-E2
Continuity mistake: The same kitchen door that led to a rather spacious laundry room in "Double, Double, Toil and Trouble" (season 4) now leads to an ordinary utility closet. (00:02:20)
Samantha Goes South for a Spell - S5-E2
Continuity mistake: The minute hand on the teakettle clock is between the 6 and the 7 when it's shown behind Samantha. When she goes to the closet, the clock reads 8:15 (minute hand on the 3). When she returns, the minute hand is between the 6 and the 7 again. (00:02:20)
Samantha Goes South for a Spell - S5-E2
Other mistake: Serena tells Darrin that Samantha won't know him back in the 19th century New Orleans because she hadn't been born yet. In Aunt Clara's Victoria Victory, we know Samantha was alive in the 19th century because she and Endora were "in Tibet at the time."
Samantha Goes South for a Spell - S5-E2
Other mistake: Darrin doesn't recognise Serena posing as Samantha. We know from "That Was No Chick, That Was My Wife" that he can tell the difference. This happens in several episodes.
It's So Nice to Have a Spouse Around the House - S5-E5
Plot hole: Darrin tells Serena that it was a good idea to have Endora babysit Tabitha. However, he wasn't even home when Endora left with Tabitha; he was unaware that a sitter was even needed. How could he have known? (00:12:40)
It's So Nice to Have a Spouse Around the House - S5-E5
Continuity mistake: The exterior of 1164 Morning Glory Circle is fake. It is not the exterior we have seen for years. They often go to a pained forested background with the fake exterior.
It's So Nice to Have a Spouse Around the House - S5-E5
Continuity mistake: Samantha removes a spell cast by some other witch; it's a series plot point in many episodes that Samantha cannot undo someone else's spells.
Samantha Fights City Hall - S5-E9
Continuity mistake: After Samantha sees the statue talking to her, her expression goes from shocked to annoyed and back to shocked in consecutive shots. Also, her hair is over both shoulders in each of the "shocked" shots but over one shoulder in the "annoyed" shot. (00:24:30)
Answer: The original diamond and white gold heart necklace was given to Elizabeth Montgomery by her then real-life husband, William Asher, who also directed the show. She wore it in nearly every early episode. When the necklace was lost or stolen about mid-way through the series, Montgomery had two replicas made from rhinestones. She wore either one of those for the rest of the show's run.
raywest ★