Rowling said that she would like to transform herself into her favorite animal: an otter. That is the Animagus shape of Hermione Patronus—which is not surprising, since Rowling has said Hermione is a lot like she is.

In Harry Potter and the Sorcerer’s Stone, dragon blood is revealed to be an effective oven cleaner.

(Source: facts.randomhistory.com)

Daniel Radcliffe wore out  60-70 wands during the making of the Harry Potter films.

(Source: hollywoodreporter.com)

To remove the tail that Hagrid gave Dudley in the hut on the rock, the Dursleys went to a private hospital where the staff was very discreet, and said that a wart had gone out of control.

(Source: mugglenet.com)

Dean Thomas’s father was killed by Death Eaters when he refused to join them. Neither Dean nor his mother know.

(Source: mugglenet.com)

A magical quill detects the birth of every magical child and records it in a book and Professor McGonagall sends an owl to each child when he or she turns eleven.

When Harry visits Mr Weasley in St. Mungo’s in Harry Potter and the Order of the Pheonix -

‘They climbed a flight of stairs and entered the “Creature-Induced Injuries” corridor, where the second door on the right bore the words ‘DANGEROUS’ DAI LLEWELLYN WARD: SERIOUS BITES.’

If you put these words on a sign, they would read:

Creature-Induced Injuries
Dangerous
Dai Llewellyn Ward
Serious Bites

Take the first word of each of these and you get “Kreacher dangerous, Die Sirius”, foreshadowing Sirius’s death and the role Kreacher played.

(Source: mugglenet.com)

Dobby wore the sock that Harry gave him in The Chamber of Secrets until the day he died.

A magical quill detects the birth of every magical child and records it in a book and Professor McGonagall sends an owl to each child when he or she turns eleven.

Muggle education is not required for wizard children prior to attending Hogwarts.