Historical Events  TV
Lassie

MMDE: Lassie saved Timmy when he fell down the well by barking

Current: The well incident never happened

Based on a real Collie

Few people realise Lassie first made her appearance in 1859 in Elizabeth Gaskell's 'The Half Brothers'. She became much more popular, though, from her movies and TV shows in the 1950's. Also, there was collie actually called Lassie who saved the life of a sailor in England in 1915.

However, the thing everyone seems to remember about her is the story of Timmy who fell down the well, when Lassie ran off for help and eventually brought it by barking frantically at her owner.

The problem is this isn't in any book, film or TV show. It's also been parodied many times - a quick internet search throws up many instances of this. So why do so many people have this false memory of it? 

Trope

Of course the producers wanted Lassie to be portrayed as intelligent, but the feeling is they jumped the shark with this one. It's such an old cliche that it's one of TV's most famous tropes, and is even a well-known joke:

Farmer: What's that, Lassie?
Lassie: Woof woof woof!
Farmer: Timmy fell down the well?!
Lassie: Woof!
Farmer: That's the third time this month, right?
Lassie: Woof woof woof woof woof. Woof woof, woof woof.
Farmer: I agree, let him get his own self out.

-- Joke

Timmy's in the well

Jon Provost was the best-known actor who played Timmy as a child (there were several), and he even titled his autobiography Timmy's in the Well with his tongue most firmly in his cheek. That's because he even points out in the book the precarious incident never happened once in all the 571 episodes. He details the numerous other things Timmy fell into, including a lake twice, a gap between railroad cars, a mine and quicksand to name but a few. Lassie's vocabulary must have been fascinating to hear of those. But nope, a well was never amongst them once.

This Mandela Effect is classed as the synopsis essence kind, the same as Luke, I am your father. That is, the entire work, in this case all the Lassie episodes, is condensed into one event that typifies the whole series for those who encounter it passively, i.e. are not fans interested enough to memorise any detail but find a trigger memory useful to "sum up" the whole show. It doesn't seem to matter that the actual event didn't happen, otherwise Scotty would have been beamed up for real.