Chances are, you wouldn't recognize McKernan with his clothes on, but that suits him just fine.
He began wearing an orange aluminum barrel to Broncos games in 1977 because of a bet with his brother.
"He wanted to see me on TV out in California," McKernan said. "I had painted a barrel to make a drum out of it to look like an Orange Crush can, told him about it and he bet me 10 bucks that I didn't have the guts to wear nothing but the barrel to a ball game."
He did have the guts to wear it and keep wearing it, through snow and sub-zero temperatures for 30 years worth of Sundays.
"The older I get, the harder it is to handle the cold," he said. "I always thought I'd go until the day I died in it."
McKernan nearly did. A few years ago, he suffered a massive aneurysm. Doctors warned he needed to give up the strenuous routine of running up and down stadium stairs as he cheered, clad only in the barrel, boots and a hat.
McKernan's wife, Becky, says he's agonized over giving up his famous act.
"The moment he puts that barrel on he has a swagger," she said. "He's very shy. That's what a lot of people don't realize about Tim."
For his part, McKernan describes himself as "just a fan."
"Just a fan" with a mission.
"The more I can get the fans into it," he said. "The better the team plays."
So he is reluctantly calling it quits. He plans to keep his season tickets and keep coming to games, just without the barrel.
"Even though I'm not gonna be wearing the can in there, Barrel Man will still be in the house," he said.
The Broncos brought McKernan onto the field prior to Sunday's game. A video montage of his years as The Barrel Man played on the big screen above.
The gruff-looking former aircraft mechanic teared up as his fellow fans erupted with applause.
"It means a lot to me," he said. "It really does."
The crowd roared as The Barrel Man snapped his arm upward into his signature Mile High salute. His wife reached up to wipe a tear from his cheek.
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