Theodor "Dr. Seuss" Geisel wrote the book "How the Grinch Stole Christmas!" in 1956. It was made into an animated Christmas television special in 1966. The special is one of four "holiday classics that runs every year on broadcast television, usually in late November or early December.
While Boris Karloff voiced The Grinch, the song about him, "The Grinch Song," is sung by Thurl Ravenscroft. If you are old enough to remember, you would recognize Thurl from voicing Tony the Tiger in the Kellogg's Frosted Flakes television commercials: "They're grrreat!"
Thurl Ravenscroft. By Source, Fair use, Link
You also would recognize Thurl's voice if you like to visit Disneyland or Walt Disney World. He does work at The Haunted Mansion, Country Bear Jamboree, The Mark Twain Riverboat, Pirates of the Caribbean, Disneyland Railroad, and Walt Disney's Enchanted Tiki Room.
Anyway, this is the classic version. Accept no imitations. First, the version with animation from the television special.
Below is the full version, without the animation.
The music was composed by Albert Hague. The song's lyrics describe the Grinch as being foul, bad-mannered and sinister using increasingly creative metaphors and synonyms, beginning with the opening line "you're a mean one, Mister Grinch". The song has six verses. Incidentally, Thurl lived a very long life, dying at the age of 91, so there is nothing dangerous about the song. :)