For the 25th year, dogs who are beautiful on the inside will converge this Friday at the World’s Ugliest Dog Contest in Petaluma, Calif. Held during the Sonoma-Marin Fair, the competition features a variety of dog contestants who show off their unconventional smiles and scruffy coats (or no coats at all) to a panel of judges.

Typically Chinese Cresteds and Chihuahuas dominate the show because of their distinguishing hairless look. But this year, dogs like Grovie the Pug and Isaboo the mutt step in to compete for the trophy.

Though some of the competition's fans appreciate its goal of celebrating unique appearances, not everyone supports this anti-beauty contest. Many veterinary health professionals struggle with the morality of promoting physical deformities, like skin diseases and eye problems, in pets.

Which one of these dogs do you think should take home the crown? Let us know what you think in the comments.

Addison

Addison

Addie is a Chihuahua who was rescued from the side of the road. One of her favorite hobbies is sleeping under the covers.

Rascal

Rascal

Rascal won this competition in 2002, and is back to reclaim his title. The 7-pound dog has some horror films coming out soon, plus a comic strip on the way.

Isaboo

Isaboo

Isaboo, who sports some impressively flowing locks, comes from the mating of a Dachshund and another competitor, Boolah.

Grovie

Grovie

This is Grovie’s fourth year entering the competition. He’s a 10-year-old Pug who enjoys sleeping on the couch.

Rue

Rue

Although some people may stop and stare at Rue, she is ready to compete in this year’s contest and hopefully bask in her ugliness.

Monkey Man

Monkey Man

This is 3-year-old Monkey Man’s second year in the competition. Despite the name, Monkey Man is actually a female dog who loves to spin in circles.

Scamp

Scamp

Named after the Lady and the Tramp character, Scamp was rescued from a shelter in Southern California and is hoping to win the big prize this year.

Princess Abby

Princess Abby

Princess Abby was crowned the World's Ugliest Dog champion in 2010 — and returns this year to regain her throne. She was rescued from the side of the road and now doesn’t stray far from her loving owner.