Its staying power has defied expectations, a Christmas song both beloved and despised.
Written as a joke more than three decades ago, "Grandma Got Run Over by a Reindeer," made famous by former Windsor resident Elmo Shropshire, is a fixture of the yuletide season.
The ballad of a grandmother who drank too much eggnog and got run over by Santa's sleigh remains a staple of radio, pops up in movie soundtracks and on ringtones.
The quirky jingle has sold 11 million copies since it was first broadcast on a San Francisco radio station in 1979, according to Shropshire, a former veterinarian who's made millions of dollars from it.
He never expected it would be so big.
"I'm always surprised at the power of the song," he said from his home in Novato. "The song was so bizarre at first. There was a buzz to hear a Christmas carol where grandma gets killed at Christmas."
Part of its appeal is the counterpoint it provides to sentimental carols about chestnuts on an open fire or being home for Christmas.
From the start, Shropshire discerned a positive underlying message to what would become his one and only hit:
"The first time I sang the song, the main thing running through my mind was &‘This proves there's Santa Claus.' I didn't think &‘Grandma's getting killed.'"
But the catchy melody and humorous lyrics delivered in Shropshire's Kentucky twang also can be an earworm to those who make a point of avoiding it.
It has perennially topped the list of most disliked Christmas songs, competing with the likes of Jingle Dogs' 1955 recording of "Jingle Bells," in which dogs woof the tune, one bark at a time.
Radio stations that specialize in Christmas formats say "Grandma" is part of the rotation for a reason.
"We, of course, conduct extensive local music research every year to find out the best Christmas songs to play — the songs our listeners like — and that's definitely one of them," said Andy Holt, program director for San Francisco's 96.5 KOIT-FM.
Shropshire, or Dr. Elmo as he prefers to be called, still gets calls from stations all over the country.
In the early and mid-1980s, and a couple years in which the song surpassed Bing Crosby's "White Christmas" as Billboard's top Christmas single, "every disc jockey in the country called me up — it was just bedlam," he said.
He did nearly 190 radio and TV interviews one year leading up to Christmas. He still does 90 to 100 each holiday season, "mostly all unsolicited," he said. And, of course, they usually involve a sing-a-long with "that Grandma song."
Shropshire and his wife, Pam Wendell, typically get into high gear by July and August with the marketing push for the Christmas season.
The song "has become such a cottage industry," he said.
It's in musical Christmas cards, a theme of Christmas ornaments, even stuffed toy reindeer at Walmart, K-Mart, Home Depot, Rite Aid, Walgreens and Safeway that have sold in the millions. Press one paw and it plays "Grandma Got Run Over by a Reindeer." Press the other paw and it changes to "Grandpa."
"It's almost as lucrative as all the record sales," said Shropshire, who by 2005 was "a millionaire five times over," according to Kiplinger's Personal Finance Magazine.