LOS ANGELES (AP) From brain-devouring zombies in ''The Walking Dead'' to crime-scene bloodshed on ''CSI,'' special-effects wizard Sam Nicholson has delivered gore galore to television viewers. But he says nothing has personally affected him more than the commercial he made for Super Bowl Sunday.
It's a rare ad urging viewers to spay or neuter their pets and uses elaborate computer-generated images and live-action shots of cats and dogs in pet-sized football helmets and pads facing off in a stadium full of cheering fans, falling confetti and exploding flashbulbs. It won't air during the New England Patriots-Seattle Seahawks matchup Feb. 1 but on one of the game-day alternatives for animal lovers - the Kitten Bowl.
The Hallmark Channel hosts the feline counterpoint to the beloved Puppy Bowl. Both are cute contests over athletic competition, with young pets romping across tiny turf fields, pushing around toy balls and pawing one another rather than scoring touchdowns.
In between cuddly cats, the commercial will promote sterilization. It's not the most crowd-pleasing cause, but animal welfare agencies say it's an effective way to reduce the number of homeless cats and dogs that are euthanized.
''I promised my best people because it was close to my heart,'' said Nicholson, owner of Stargate Studios. ''I believe in the cause.''
The ad is the brainchild of Lucy Pet Foundation founder Joey Herrick, whose group aims to start up a fleet of spay-and-neuter vans to travel wherever dog or cat overpopulation is a problem.
His foundation launched a social media campaign in the hope scores of people will see the ad, which pans into a stadium where live-action pets in uniforms face off in a mock championship, barking to hike the football, catching it in their mouths and getting cheers from real and computer-animated animal fans.
Nicholson fused computer-generated images with live-action video and as many as 80,000 individual photos of dozens of pets brought in by staff members or rescued from shelters.
While the pets in the audience got lessons in quick changes, the dogs and cats on the football teams took fast-tracked training on how to be comfortable under the weight of shoulder pads and helmets. Nicholson said he shot all the parts, then pieced them together like a large, layered puzzle.
''All the dogs and cats in the stadium are individually photographed elements, dressed in every outfit we could think of,'' Nicholson said. ''We synchronized them so they looked left to right when the ball was going that way.''
To get the dogs to look from one side to another, someone would run behind the camera with a hot dog. For cats, they put kitty food on a stick and ran.
Nicholson photographed most of the animals in front of a green screen to eliminate distractions.
''We used the same dogs in sunglasses, lots of wardrobe changes, crazy hats and tutus - all dressed up - cats in muscle suits, Chihuahuas in ballerina outfits,'' he said.
The ad would have cost about $1 million, Nicholson said, but he donated nearly 90 percent of it toward the foundation's cause. Herrick's organization believes overpopulation is the biggest challenge to animal welfare: Shelters euthanize millions of unwanted cats and dogs every year.
''You have to stop the influx,'' said Herrick, who created a mobile spay-and-neuter clinic in Thousand Oaks, northwest of Los Angeles. ''There are too many animals coming in.''