Puppy Bowl assistant referee will miss calls. Give her a break, though, she's just a dog!

First, the good news on Sunday's Puppy Bowl.

Puppy Bowl XX, the 20th anniversary dog-fest in a mutt-size football stadium, is living up to the hype as "Most Puppiest Puppy Bowl Ever!" with a record 131 pooches from 73 shelters nationwide.

For the first time, there will be adorable canines in vital nonplayer positions including assistant referee Whistle, who joins Dan Schachner, the onetime NFL referee who has been judging the contest for the past 13 years.

The ruff news? The new dogs are hopeless at their jobs, especially Whistle, a Bichon Frisé/poodle mix being fostered by Schachner. "Whistle is terrible at calling penalties and instilling respect from the players. She gets walked over, sometimes literally," says Schachner. "But she sure is cute."

Here's what you need to know about the three-hour Puppy Bowl XX (2 p.m. EST/11 a.m. PST, simulcast on Animal Planet, Discovery, Discovery+, TBS, TruTv and Max).

When was the first Puppy Bowl?

Twenty years of the Puppy Bowl is a big deal for the event held annually on Super Bowl Sunday since 2005. More than 1,400 puppies, 3 to 6 months old, have been featured and found forever homes.

"It's wild to think about two decades," says Schachner. "In dog years, that's like two lifetimes."

Puppy Bowl XX commemorates the milestone by bringing back four dogs from past events to be inducted into the all-new Puppy Bowl Hall of Fame, including 2015 Puppy Bowl standout Bubba, now 9 years old.

"When you go back and look at our old-timers, they're fully grown adults and sometimes senior dogs," says Schachner. "It's pretty incredible to see the passing of time."

The game will field a roster of pups from the perennially opposing sides − Team Ruff and Team Fluff − frolicking and sniffing butts on the turf field in a way that sometimes resembles football. There will be six dogs with special needs, including pug terrier Riddle, who has the neurological condition cerebellar hypoplasia, and Mr. Bean, a papillon who has only two hind legs.

The show will include the all-time smallest pup, Sweetpea, a 1.7-pound Cavapoo, and the biggest, Levi, a 72-pound Great Dane.

Be advised: Accidents will happen on Puppy Bowl, which already has been filmed and is being edited for broadcast. "This is not the Westminster Dog Show, we're showing these puppies in their untrained glory. Poops and pees happen all the time," says Schachner. "We show them occasionally to say, 'This is part of the reality.' "

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All of the dogs are available for adoption, with the caveat that they're so cute, they're going fast. Many have already been adopted, including by the Puppy Bowl crew. "We're transparent about that. Our goal is to find them their forever home," says Schachner. "Seven have been adopted by the crew, which is a record, from a show editor to the network president."

Sportscasters Steve Levy and Taylor Rooks return to provide play-by-play commentary along with favorite elements such as the slo-mo cam, the water-bowl cam and kitten spectators in the Temptations Sky Box.

But the 20th edition is all about the increased support staffing, with dog coaches on the sidelines, an all-dog cheerleader section, dogs in the TV control room and even dogs "working" the camera.

Schachner, who will wear a GoPro for a new camera angle, jokes that the Puppy Bowl is moving toward an all-dog crew by the next 20-year anniversary. This could put his role at risk if Whistle grabs attention. "My job might be in jeopardy," says Schachner. "Whistle is going to reapply for the position next year. We'll see what happens. All I can say is stay tuned."

This article originally appeared on USA TODAY: When is the next Puppy Bowl? 2024's contestant lineup is pooch-perfect