Grim

"The giant, spectral dog that haunts churchyards! My dear boy, it is an omen&mdash;the worst omen&mdash;of death!"

- Sybill Trelawney discussing the Grim with Harry Potter.

The Grim is an omen of death, which is reputed to bring about the demise of the person who encounters it. The Grim takes the shape of a large, black, spectral dog. Perhaps the most well-known of omens, the Grim has earned infamy throughout the wizarding world and is considered to be one of the worst, if not the worst, omens around.

Harry Potter's 'encounters'
In 1993, after accidentally inflating his aunt, Marjorie Dursley, Harry Potter runs away from 4 Privet Drive, and by the time he reached Magnolia Crescent he witnessed "the hulking outline of something very big, with wide, gleaming eyes". Shocked, he steped backwards and fell off the kerb, into the street, and inadvertantly summoned the Knight Bus to his rescue. By the time Harry had got back up again, the creature has vanished. Harry, describing it as "like a dog... but massive", departed for Diagon Alley. Whilst in Flourish and Blotts in Diagon Alley, he noticed a book, entitled Death Omens: What to Do When You Know the Worst is Coming with the front cover depicting a large black dog with gleaming eyes, strikingly similar to the one he witnessed on Magnolia Crescent.

The term 'Grim' was only first mentioned to Harry by Professor Trelawney during a Divination lesson studying the art of Tessomancy. When the tea leaves revealed the Grim, a horrified Professor Trelawney informed Harry, that the Grim is the possible omen of death. Harry's stomach "lurched" upon remembering he had witnessed the dog Magnolia Crescent.

Later, during a Gryffindor versus Hufflepuff Quidditch match, Harry saw a "the silhouette of an enormous shaggy black dog" in the topmost empty row of seats, which wildly distracted him. When he glanced back, the dog had disappeared. Seconds later approximately one-hundred Dementors entered the proximity of the stadium, causing Harry to fall unconcious, plummeting fifty feet from his broom.

The 'Grim' Harry witnessed on multiple occasions was revealed to be Sirius Black in his Animagus form, who had recently escaped from Azkaban Prison. Therefore, Harry actually never witness the Grim, only believing he had done so. Although he was prophecised the Grim by Trelawney, like many of her other prophecies, it did not come true.

Scepticism regarding the Grim
"There you are then. They see the Grim and die of fright. The Grim's not an omen, it's the cause of death!"

- Hermione Granger arguing with Ronald Weasley.

Hermione Granger highly doubted the Grim's status as an omen of death, thinking that if the Grim even existed, it was most likely the cause of death rather than an omen, as people who ever saw it would die of fear; she took Ron's claim that his Uncle Bilius died twenty-four hours after seeing a Grim as proof to her belief. Also, the assistant in Flourish and Blotts may have expressed a degree of scepticism, as he discouraged Harry from buying Death Omens: What to Do When You Know the Worst is Coming, saying "Oh, I wouldn't read that if I were you. You'll start seeing death omens everywhere, it's enough to frighten anyone to death".

Behind the scenes

 * The chapter in which Harry falls from his broom during a Quidditch match after seeing what he believed to be the Grim is aptly named "Grim Defeat".
 * The Grim appears to be based on the Black Shuck, a black dog which also forsees death.
 * The Grim may also be based on the Barghest, a large black dog in English legend.

Appearances

 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Prisoner of Azkaban (film)
 * Harry Potter and the Deathly Hallows

Notes and references
Sinistros Kalmakoira Ponurak