Boo. It's Halloween. Go put on a Zenyatta mask and frighten the neighborhood Curlinistas.

The idea that the unbeaten 4-year-old filly might unseat the reigning Horse of the Year is unsettling, particularly when the champ has had a pretty good year. But in the wake of Zenyatta's victory and Curlin's loss in separate Breeders' Cup events over Santa Anita's synthetic main track, a movement has bubbled. Gary West, leading the charge on his Fort Worth Star-Telegram blog, tried to stick a quick finger in the dike.

TUCSON, Ariz. - Where was Paul Revere when we needed him to warn the folks at Santa Anita that the British were coming? He could have at least ridden to Lexington - Kentucky, not Massachusetts - to alert breeders that things have changed, and they better study the lessons.

It may be too early to assess the full impact of Saturday's British invasion - they won four Breeders' Cup races, led by the impressive victory by Raven's Pass in the Classic - but it's not too early for the skilled turf writers of England.

ARCADIA, Calif. - On a backstretch crossroads last Saturday afternoon, John Gosden was following Raven's Pass over for the Breeders' Cup Classic when he broke stride briefly to acknowledge Steve Asmussen.

"Congratulations, Steve," Gosden said. "He's a remarkable horse."

"Thank you," Asmussen replied. Then he fell in behind Curlin.

ARCADIA, Calif. - Since the introduction of synthetic racetracks in the United States, bettors have struggled to understand them, and leaders of the industry have debated their merits. But after the Breeders' Cup was contested over a synthetic surface for the first time, and European colt Raven's Pass upset America's best horse, Curlin, the outcome surely will crystallize fans' ideas about synthetics. It should also stimulate an intensified discussion about the proper place of these tracks in the spectrum of American racing.

ARCADIA, Calif. - Leaders of the racing industry regularly say that the sport needs Thoroughbred stars who can attract the attention of the general public and create new fans.

Well, the sport has one in Zenyatta. She's a filly. She's undefeated. She has an electrifying style that any fan can appreciate: Zenyatta typically trails all her rivals until she blows past them with a powerful late move.

ARCADIA, Calif. - The impact of the Breeders' Cup has been debated since its inception. It has been hailed as a reason for the general public to care about Thoroughbreds beyond the Triple Crown. It has been described as nothing less than racing's own Super Bowl. It has been criticized for dimming, even dooming, traditional late-season events, and decried for its disproportionate influence on determining the champions of the game.

ARCADIA, Calif. - Curlin would ordinarily be the cynosure of the Breeders' Cup. The defending U.S. Horse of the Year and the top money-winning North American Thoroughbred of all time is favored to end his career with a victory in the $5 million Breeders' Cup Classic.

NEW YORK - The inaugural Filly Friday is a microcosm of a Breeders' Cup in transition, featuring some of the best and worst aspects of a championship event that has been radically reinvented for its 25th running.

ARCADIA, Calif. - John Gosden was going to be the next Charlie Whittingham. You in the back, knock off the hair jokes. Yes, Gosden's tresses were on the retreat by the time he left California, in 1988. But his star was very much on the rise, sparked by the Breeders' Cup Mile victory of Royal Heroine in 1984, and his stable was beginning to resemble nothing less than a budding microcosm of the institution located down the road, trained by that bald ex-Marine.

ARCADIA, Calif. - It's tough to give Greg Gilchrist a hard time for his 0-for-3 record in the Breeders' Cup, even though he's tried to win the Sprint with a heavy favorite and two second choices. Anyway, he's the last guy in the world to pass the buck.