There are obviously some MASSIVE spoilers ahead! And #5 mentions pregnancy loss.
1. First, in the pilot episode of Succession, Roman Roy appears with a woman and child — and he's wearing a wedding ring. Then, they were never seen again. Most fans pointed out that the show simply forgot about Roman's family, with Kieran Culkin saying it was later explained to him that it was just "his girlfriend, and she had a child."
2. In Prison Break, Sara was notably killed in a gruesome fashion, with her head literally being delivered to Lincoln and Michael as a warning. It was a heartbreaking death that was later reversed when she came back alive in Season 4. The show explained that it wasn't actually Sara's head in the box but rather another woman who looked like her.
3. Family Matters originally centered heavily on the Winslow family, however, after audiences loved Steve Urkel so much, the central storylines on the show shifted. This led to the youngest Winslow daughter, Judy, disappearing one day as if she never existed. People often joke that Judy went upstairs one day, and never returned.
4. In The Big Bang Theory, Sheldon notably revealed that he does his signature triple knock before entering because he once accidentally walked in on his father cheating on his mom with another woman. However, in Young Sheldon, the story changes, with Sheldon actually catching his parents engaging in role-play, with his mom wearing a blonde wig.
5. In Married...with Children Season 6, Peg is pregnant; however, a few episodes later, it was revealed that it wasn't real, and Al dreamt it. This storyline was originally created when Katey Sagal was pregnant in real life, but then her child was stillborn while filming the season. The writers made the choice to reverse her character's pregnancy storyline on the show following the news.
6. In The Vampire Diaries Season 1, Stefan is the first Salvatore brother Elena meets in Mystic Falls. However, seasons later, it was revealed that Elena actually met Damon before she met Stefan, but he used compulsion to make her forget.
7. In the series finale of Roseanne, Roseanne reveals that she's actually been writing her book and she changed details, with a big one being Dan died of a heart attack. When the series was rebooted in 2018, the show decided to make it so Dan was still alive.
8. Fringe Season 2 introduced FBI agent Amy Jessup, who was played by Meghan Markle before she landed her breakout role in Suits. Although she was seemingly setting up a big storyline involving the Fringe Division's case files, she suddenly just vanished after only two episodes.
9. When Happy Days began, Richie originally had an older brother named Chuck. He appeared in the first two seasons of the series before just disappearing as if he never existed. In his place, Fonzie became a bigger character and acted as an older, brother-like figure for Richie.
10. Similarly, in The West Wing Season 1, Moira Kelly starred as Mandy Hampton, a White House media consultant who was a main character. However, when Season 2 began, Mandy was gone. The disappearance of her character even led to fans coining the term "Mandyville," which was used when any other character just vanished during the show's run.
11. In the Riverdale pilot episode, when Cheryl talks about the cheerleading squad, she mentions that she's the "senior captain." It's also assumed that Jason Blossom, Cheryl's twin, is older than the other main characters. However, eventually, Cheryl becomes the same age as Archie, Betty, Jughead, Veronica, and more.
12. In Season 8 of Cheers, Frasier mentions that his dad was a scientist and is dead. However, when Frasier premiered four years later, Frasier's dad, Martin Crane, was a central and beloved character.
13. And finally, in Dallas, Bobby tragically died in the Season 8 finale while saving Pam. Then, an entire season went by, aka 31 episodes, before Pam woke up and it turned out it was all a dream, and Bobby was alive. Nicknamed "The Dream Season," it remains one of the biggest retcons on TV.
