GETTY IMAGES/Justin Sullivan
A dog named Ringo wears a mermaid costume as he greets a dog wearing a lobster costume during the first annual "Howl-o-ween" dog costume contest Oct. 31, 2007, in San Francisco. The event benefits the Society for the Prevention of the Cruelty of Animals.
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Jasmin dresses like singer Britney Spears during a doggy costume contest in West Hollywood, Calif., Oct. 28, 2007.
GETTY IMAGES/Mario Tama
Rudy, left, poses as Michael Jackson and Parker poses as his girlfriend in the "Thriller" video during the 17th annual Tompkins Square Halloween Dog Parade Oct. 28, 2007, in New York. The event is the largest dog Halloween party in the United States.
GETTY IMAGES/Chris McGrath
A dog dressed as a bumblebee poses during the 17th annual Tompkins Square Halloween Dog Parade Oct. 28, 2007 in New York.
GETTY IMAGES/Chris McGrath
Bon the dog poses as an iPhone during the 17th annual Tompkins Square Halloween Dog Parade Oct. 28, 2007, in New York. The event is the largest dog Halloween party in the United States with an annual attendance of over 400 costumed dogs.
GETTY IMAGES/Mario Tama
Chiquita poses as Queen Elizabeth during the 17th annual Tompkins Square Halloween Dog Parade Oct. 28, 2007, in New York. The event is the largest dog Halloween party in the United States with an annual attendance of over 400 costumed dogs.
AP Photo/Wilfredo Lee
Sabrina, left, a mini pinscher, and Giselle Mayer, 3, dance at a dog park during the Belle Meade neighborhood dog parade and costume party in Miami Sunday, Oct. 28, 2007.
AP Photo/Wilfredo Lee
Maggie, 9, rests in the grass at a dog park during the Belle Meade neighborhood of Miami Sunday, Oct. 28, 2007. The neighborhood hosted a dog parade and costume party.
GETTY IM AGES/ Steven A. Henry
A dog dressed as Superman sits on the red carpet at Animal Fair Magazine's 7th Annual Canine Halloween Pet Costume Party at Arena on Oct. 26, 2007, in New York, N.Y.
AP Photo/Lisa Poole
Tiny Gonsalez, a long-hair Chihuahua, of Boston, wears a cowboy costume, Saturday, Oct. 27, 2007, during a dog and cat Halloween costume contest at a department store in Boston.
AP Photo/Al Maglio
An orange canine named Pumpkin Dog shows his Halloween spirit as a participant in the Truman State University homecoming parade Saturday, Oct. 27, 2007, in Kirksville, Mo.
AP Photo/Florida Keys News Bureau
Mark Friga of Rochester, N.Y., holds his dog Olivia while awaiting to compete in the WKEY Pet Masquerade Contest Wednesday, Oct. 24, 2007, in Key West, Fla. The "It's amazing what a grown man will do for his dog," Friga said.
AP Photo/Florida Keys News Bureau
James Brooks, a public information official with the U.S. Navy, leads his Navy fighter jet-garbed-dog Brutus off the stage Oct. 24, 2007, at the WKEY Pet Masquerade Contest in Key West, Fla. The event was one of more than 30 during the island city's 10-day Fantasy Fest costuming and masking festival that began Oct. 19.
AP Photo/Florida Keys News Bureau
Kelsey Morris, 7, and her duck Prissy, await the start of the WKEY Pet Masquerade Contest Oct. 24, 2007, in Key West, Fla. The competition was one of more than 30 costuming and masking events during the island city's 10-day Fantasy Fest that ends Sunday. A parade, set for Saturday night down Duval Street, the island's main road, is expected to attract some 60,000 revelers.
AP Photo/Florida Keys News Bureau
Lisa McGann of Tampa, Fla., adjusts a bandana on her tortoise Gammerita Wednesday, Oct. 24, 2007, at the WKEY Pet Masquerade Contest in Key West, Fla.
YOSHIKAZU TSUNO/AFP/Getty Images
Hitomi Onozuka and her dog dressed as pumpkins during an annual contest for Halloween, in Kawasaki, Kanagawa prefecture, Japan, Oct. 21, 2007. Some 30 owners showed off their dogs and cats wearing fancy costumes.
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A costumed cat looks festive as a jester during an annual Halloween contest in Kawasaki, Japan, Oct. 21, 2007. Some 30 owners showed off their dogs and cats wearing fancy costumes.
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All aboard! A woman pushes a carriage decorated like a pumpkin Oct. 21, 2007, in Kawasaki, Japan. Peering from inside are her two decorated dogs.
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An angelic dachshund poses for the cameras Oct. 21, 2007, in Kawasaki, Japan. The pooch was among 30 animals dressed for the annual costume contest. Veterinarians warn not to take your dog along trick or treating. Even typically calm dogs may get spooked by excited voices and strange costumes.
YOSHIKAZU TSUNO/AFP/Getty Images
A pumpkin-topped Pomeranian poses during an annual Halloween contest in Kawasaki, Japan, on Oct. 21, 2007. Some 30 owners showed off their dogs and cats wearing fancy costumes.