It's a bushy, multicolored masterpiece that he has grown out since the 2015 season. It's also now a little lighter than it was before his game against the Toronto Maple Leafs on Thursday night, after a chunk of it was ripped out during a fight.
Thornton and Leafs center Nazem Kadri traded slashes before the opening faceoff. After getting thrown out of the circle by the linesman, they dropped their gloves for a fight just two seconds into the Sharks' 3-2 shootout loss in Toronto.
At the end of the tilt, which featured Kadri skating away from Thornton while the Sharks center connected on a few blows, a large hunk of whiskers from Thornton's beard hit the ice like a tumbleweed, having been snatched from his face by Kadri.
"I ended up with a piece of it in my hand," Kadri said. "I have no idea how that happened.
"I thought I was a hockey player not a barber. I didn't mean to grab him there. I mean, he's a big boy. I couldn't reach all the way across his shoulder. I felt like I just grabbed him in the middle of his jersey and just came down with a handful of his hair.''
Thornton didn't comment after the game.
As Thornton was in the penalty box following the fight, the beard trimming eventually ended up on the Sharks' bench. Specifically, it ended up in the catching glove of backup goalie Aaron Dell, who showed it off to teammates.
"We were trying to figure out what it was,'' Sharks forward Chris Tierney said.
Kadri, who was giving up at least 4 inches and 30 pounds to Thornton, had a welt on the side of his face as a souvenir of the fight.
"I didn't see that coming," said former Shark Patrick Marleau.
Thornton, 38, is in his 20th NHL season and has eight goals and 19 assists in 27 games for the Sharks. This was his second fight of the season, and by far the hairiest.
The Associated Press contributed to this report.