Michael's turn carrying the Jerkass Ball climaxes with him swiping Mary Poppins' magic compass. Instead of naming the four directions one at a time, he quickly says all of them in a row. This causes everyone that Michael and the others met during their first journey with the compass to surround him with bloodthirsty expressions.note In the 1934 version, the racial stereotypes direct weapons towards Michael. The sight scares Michael into dropping the Jerkass Ball by the time Mary Poppins swoops him back to the nursery.
Mrs. Corry breaking off her candy fingers and feeding them to the children comes off as this to readers who see it more as Body Horror than a hospitable act.
Time marches on. In Maurice Maeterlinck's extremely popular 1908 play "The Blue Bird", the anthropomorphic character Sugar breaks off two of his fingers and offers them as candy sticks to the child protagonists; similarly, the character Bread gives them slices of his belly. The play was still very well known when the Mary Poppins books were written.
The Holy Terror herself, Miss Andrew in a nutshell.
After Jane takes out her frustrations at being the eldest Banks child by punching Michael, Mary Poppins forbids her from attending a tea party at Miss Lark's house. Home alone, Jane pays a visit to some boys who reside in the design of an antique Royal Doulton bowl. When she asks to go home to her family, the boys' great-grandfather tells her that when she entered the bowl, she also became teleported 60 years into the past. With her parents not yet born, it looks like Jane must live as a Fish out of Temporal Water, and the youngest sister of boys who are Older Than They Look...until Mary Poppins whisks her back into the real world. Upon returning to her own time, Jane wholeheartedly accepts her responsibilities as the eldest Banks child. Mary Poppins Returns includes this bowl, but in a Lighter and Softer turn, it just leads to a world of singing cartoon animals.note ...who still try to kidnap the Banks children.
Michael has a similar experience in one of the other books, after journeying to a star inhabited by talking cats. He becomes seemingly unable to return home because time passes more slowly on the star than on Earth, and during the time he spent with the cats, everyone in Michael's family died. Their house also became abandoned. Fortunately, Mary Poppins rescues him again, and takes him back to his own time.
The 1964 Disney Movie
When Jane and Michael flee the bank through an alleyway, and encounter a creepy old lady, a large black dog, and a shadowy figure. Fortunately, the latter is just Bert covered in soot. It doesn't even help that the old crone they ran into was played by Betty Lou Gerson, the voice of Cruella De Vil.
The nursery-cleaning scene. The jerky Stop Motion special effects have not aged very well. A popular parody trailer on YouTube demonstrates that with an audio/soundtrack swap, it almost looks like a deleted scene from Poltergeist.
Bert's verse of "Chim Chim Cher-ee" where he sings about "the chimney sweep world" is very accidentally unnerving and sinister sounding. Particularly how he ends it with an almost maniacal smile after singing "on the rooftops of London...coo', what a sight!"
Just... the way Dick Van Dyke reads the line, "Where there's hardly no day, nor hardly no night, there's things half in shadow...and halfway in light". Chills, man.
The end of Bert's "Comical Poem", for the same reasons, as it very suddenly shifts from happy carefree lines to a description of what he feels in the air. Of course we learn, as Bert presumably knew, that "what lies in store" is good, but the line itself, Dick Van Dyke's delivery, and the atmosphere around it, can be very eerie. Even Bert's return to a more carefree performance fails to fully relieve the scene of its eeriness, perhaps even adding to it due, again, to the sharp contrast.
Wind's in the east, mist coming in. Like something is brewing, about to begin. Can't put me finger on what lies in store, but I feel what's to happen all happened before.
The crazy expression on the face of Michael's merry-go-round horse is very uncanny valley.
The 1983 Soviet movie "Mary Poppins, Goodbye"
While Robertson Ay is singing a cheerful song about cows and milk, in the background one can see a poster for the 1982 French thriller/horror movie Invitation Au Voyage. In this movie, the protagonist's twin sister (and lover) dies while taking a milk bath, and for the duration of the movie, her brother drinks this milk and gradually transforms into her. The song ends with the Banks children bringing Robertson a glass of milk; knowing this subtext gives the scene a decidedly Squicky feel.
The Play
The stage musical features a new, scary number called "Temper, Temper" where Jane and Michael's toys grow bigger than they are, come to life, and put them on trial for losing their tempers and breaking a toy. Remember all the mean things you did to your toys? Cover your children's eyes... and your own.
The song was deemed so scary that it was replaced with 'Playing the Game' in later productions (eventually making its way to the Broadway production). It was also part of the reason the producers would not allow any child under the age of three into the theatre during its London run and stated that the show was meant for children age 7 and up.
As if that on it's own wasn't bad enough, the original London production had the song end with Jane and Michael in front of a firing squad with the song ending just as the toys fire at them. Toy Story ain't got nothing on this...
The West End revival takes 'Playing the Game' and brings it closer to the original "Temper, Temper" with a giant Mr. Punch puppet judging the Banks children's tempers.
There's also Miss Andrew who, in the original productions, ended up being locked in a cage and sent to Hell. By Mary Poppins herself. Good Is Not Nice indeed...
parody trailer on YouTube demonstrates that with an audio/soundtrack swap, it almost looks like a deleted scene from Poltergeist.