"The skull... danger in your path, my dear...."
-- Madam Trelawney (PA6)
Tea leaf symbol from Unfogging the Future meaning “danger in your path.”
- Months after Trelawney saw the skull omen in his teacup, Harry eventually met Sirius Black and was struck by his deathly appearance: If eyes hadn't been shining out of the deep, dark sockets, he might have been a corpse. The waxy skin was stretched so tightly over the bones of his face, it looked like a skull. His yellow teeth were bared in a grin. It was Sirius Black (PA17).
- Trelawney may have foreseen the march of Lord Voldemort's Death Eaters at the Quidditch World Cup campground as the green skull of the Dark Mark hung above them in the sky, the spell "Morsmordre" cast by Barty Crouch Jr.'s House Elf, Winky (GF9). The same Dark Mark is magically tattoo'd on the arms of the Death Eaters and burns when they are summoned by the Dark Lord (GF36).
- Hermione read about Voldemort's skull-and-snake Dark Mark in a book called The Rise and Fall of the Dark Arts (GF9)
The skull is always a symbol of death, from the skull and crossbones on a bottle of poison, to skulls which adorn ancient graves. Medieval people became fascinated with the idea that Death, personified as a skeleton, comes for everyone, both the peasant and the king. This was depicted by artists as a "Danse Macabre" or "Dance of Death." source: Wikipedia
Composer Camille Saint-Saens wrote his version of the Danse Macabre in 1874, and in 1999 it was used as background music on Buffy the Vampire Slayer episode "Hush" about creepy demons with skull-heads known as "The Gentlemen" stealing people's hearts while they slept. source: Wikipedia