Sometimes in films, there is a scene that doesn't fit, but there is a reason for it being in there - usually to explain or foreshadow something that will occur later in the film.
Other times, things will happen that never get brought up again, and no-one - except for the director, probably - hasn't the faintest idea why it is in there. Like these...
8. The dream sheep in A Nightmare on Elm Street
The opening scene of the original Nightmare on Elm Street saw Tina - who we thought was the main character - being stalked and attacked by a disfigured man wearing a blade-fingered glove that we would soon come to know as Freddy Krueger.
While Tina is walking through the boiler room in her dream, a sheep randomly runs past, and is not seen again.
Reportedly, the script states "there is no reason for this" - as the makers probably wanted to throw it in as one of those surreal things that happen in dreams, but fans have theorised that it has to do with a sheep's innocence, Tina being a lamb to the slaughter, or counting sheep to help you sleep.
7. Mr Freeze's carol singers in Batman & Robin
Joel Schumacher's Batman & Robin is by far the worst and most hated Batman movie, and features some pretty unwanted issues, including Bat-nipples and Mr Freeze's endless ice-related puns.
But things get even more unusual with Mr Freeze, when the Batman villain is seen in his hideout, wearing a robe and cosy polar bear slippers, demanding that his henchmen sing along to the song 'Snow Miser' from the 1974 Christmas special, The Year Without a Santa Claus.
Never mentioned again in the movie, the scene sticks out as the most pointless and daft, even in a movie full of silly set pieces and dialogue (and a visibly bored George Clooney).
6. Ray's supernatural pleasure in Ghostbusters
During a montage of the Ghostbusters' success, there is a scene inserted in which Ray is dreaming about a beautiful ghost floating above him who then unzips his flies as he goes cross-eyed.
In the middle of a family film, this moment sticks out as an unnecessarily adult joke, and is never mentioned afterwards, which serves to worsen how out-of-place it is.
The scene was a deleted scene that the makers found it so funny that they re-inserted it back into the movie - the scene saw the visit from an amorous spectre after Ray fell asleep investigating an old military fort... which brings on even more adult implications.
5. The fat lady in the painting in Harry Potter and the Prisoner of Azkaban
It would take something quite irreverent to count as a wtf moment in the Harry Potter series, but in the Prisoner of Azkaban, there's an unexplained moment that is never referenced again.
In a Hogwarts Castle is a portrait of a fat lady that guards the entrance to Gryffindor Tower, and when the boys give her the password to enter, she is too busy trying to break a wine glass with her opera singing.
She smashes the glass against a column behind her and feigns amazement at her singing skills before conceding and letting the boys through.
Expanding and adding humour to the character that was played by Elizabeth Spriggs in Philosopher's Stone, much-loved British comedienne Dawn French played the fat lady and added another bit of wonder and comedy to the wizarding series.
4. Tinkerbell becomes human-sized in Hook
The scene that stands out in the already fantastical Robin Williams retelling of the Peter Pan story is when Tinkerbell grows human-size and professes her love to Peter.
Steven Spielberg wrote it in to appease Julia Roberts, who was unhappy that she had to film all of her scenes as Tinkerbell alone in front of a green screen.
Roberts, who insisted she had at least one scene with another actor, was given her chance in which she grows human-sized and professes her love to Peter, but he turns her down for his wife and children, which stands out as a bizarre moment in an already pretty wild movie.
3. The Zion rave in The Matrix Reloaded
After the first Matrix movie blew audiences minds with its innovative plot and impressive special effects, everyone was expecting more of the same from the two hotly-anticipated sequels.
Early into The Matrix Reloaded, after Morpheus had performed a rousing speech to the people of Zion, they then break out into a full-on rave for the better part of five minutes.
To add to the oddness, interspersed with the scenes of the rave is a sex scene between Neo and Trinity.
For one thing, it did help to serve as a point to viewers that The Wachowskis had got carried away with their own big-thinking ideas and included loads of confusing and unnecessary scenes and set pieces which would follow over the two sequels.
The scene is supposed to illustrate the difference between the passionate, chaotic and animalistic humans, against the cold, calculating and emotion-free machines - but what audiences actually saw was characters which had no importance to the plot bumping and grinding for an extended period.
2. The jazz club scene in Spider-Man 3
Spider-Man 3 is the prime example of a film which should have been amazing only to be ruined by studio interference, as well as the rule of the threequel (there must always be three villains).
Despite it being quite messy as it is, there's an especially unusual sequence that sticks out, and that is emo Peter and his dance performance in the jazz club.
After getting dumped by Mary Jane Watson, he attempts to make her jealous with his elaborate and cringey routine - aided by his spidey superpowers.
Director Sam Raimi had either got sick of all of the studio interference and didn't care about the film anymore, or knew it was going to be a dud so had some fun with it.
1. The tunnel scene in Willy Wonka and the Chocolate Factory
One of the most famous WTF moments in film history is the tunnel scene in the 1971 classic Willy Wonka and the Chocolate Factory.
After enjoying the first room of Wonka's factory, a lovely scene in which everything is made of chocolate - including a chocolate river, the winners (minus Augustus Gloop) step aboard a boat which floats into a tunnel and things take a turn for the horrific.
Lights flash, disturbing images of insects and animals being eaten are projected on the walls, while Gene Wilder sings a song that grows more demented.
Then, all of a sudden, the ride is over and they move on to the next room; while this sticks out as an irrelevant and creepy moment in an otherwise family-friendly film, it is perhaps an indication to the children (and audiences) of Wonka's eccentric and unpredictable nature.