The Grandfather Clock is a supernatural item found in the Haunted Mansion.
Appearance
The Grandfather Clock is an occult gothic clock with anthropomorphized detailing making it's upper-half look like a demonic face, it's pendulum look like a a devil's tail, and it's legs looking like animal claws.
The Clock appears in the Corridor of Doors with it's face glowing green, and it's crooked hands moving backwards past the number 13 in the place of 12. As guests pass by in their Doom Buggies a shadow of a human-like talon passes in front of the face of the clock.
During Haunted Mansion Holiday, a tag found on the clock says, "To Leota, Special Gifts for you -Sandy Claws" implying that it was a gift given to Leota by Jack Skellington.
Trivia
Every park has a different variation of the clock's hands, in Walt Disney World the hands resemble skeleton fingers, in Disneyland they resemble leeches and when aligned correctly make up the silhouette of a bat, in Tokyo they are simply ornate artistic hands not resembling anything, and in Disneyland Paris' Phantom Manor they resemble snakes.
In unused Ken Anderson concept-artwork for the Black Cat incarnation of the ride, the clock closely mirrors a scene from Edgar Allan Poe's gothic-horror short story, "The Pit and the Pendulum" where a man kidnapped by Spanish Inquisitors and is tortured by a giant clock's swinging blade-like pendulum as rats claws across his body.
A sentient grandfather clock appears in Rolly Crump concept art for the Museum of the Weird, this grandfather clock was visually inspired by a similar coffin clock in the 1933 Mickey Mouse short, "The Mad Doctor".
The way that the shadow-claw moves across the clock face mirrors a scene from the 1922 horror film Nosferatu in which a vampire uses the shadow of his talon to molest a woman as well as the 1932 film adaption of Edgar Allan Poe's "Murders in the Rue Morgue" where a gorilla strangles a woman to death in her sleep.
The Number 13 is commonly associated with the occult and the supernatural for many reasons including but not limited to; the 13th disciple at the Last Supper having had been Judas, Ancient Mathematicians deeming 12 the perfect number, and several non-Christian faiths considering 13 to be a holy number only for the christian church to demonize it as a way to absolve their cultures.
