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)
Other mistake: Samantha is reading a 4-line note from Endora. The paper is semi-transparent and in a shot from the front, we can easily see the writing through the paper. However, after the note is "twitched" into a second, shorter note, there's another shot from the front - and the lettering looks exactly the same as it did before. (00:16:40)
Revealing mistake: When Endora goes to Darrin's workplace and puts the spell on him she appears to be floating. Look closely and you can see the wires holding her up.
Revealing mistake: When Samantha and Bombay are at the top of Mt. Everest, Samantha's shadow can be seen on the "sky" behind the rock revealing a blue backdrop.
Marriage, Witches' Style - S5-E21
Revealing mistake: The wires holding the cake knife are visible as it's cutting a slice. (00:00:25)
Marriage, Witches' Style - S5-E21
Revealing mistake: In addition to Samantha, Elizabeth Montgomery also played Serena. In scenes where both characters appeared, Elizabeth would face the camera and play one character and another actress, Melody McCord, would play the other with her back to the camera. But in this scene, when Mr. Beams tells Serena she has a luncheon date with her intended at the rotisserie, Melody (portraying Samantha), with her back to the camera, inadvertently turns her head, revealing her face. (00:07:20)
Marriage, Witches' Style - S5-E21
Revealing mistake: At the end of the episode, during Serena and Samantha's second meeting with Mr. Beams, in the wideshots of the two women sitting on the couch and also when they're both poking their heads through the doorway, Serena's body double actually appears face-forward. Additionally, in the closeups of Serena and Sam on the couch, both are played by Elizabeth Montgomery, and we can see the wall's color difference behind them due to the use of the split-screen technique. (00:22:25)
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 ★