Uncle O'Grimacey on the green Chicago River.McDonald's

Uncle O'Grimacey, the McDonald's mascot who was once rumored to have IRA links, was in Chicago this weekend for the uniquely Irish American tradition of dyeing the Chicago River green for St. Patrick's Day.

First conceived some 50 years ago, Uncle O'Grimacey - Grimace's Irish uncle, obviously - was rebooted this year as part of McDonald's USA's campaign marking the 50th anniversary of its Ronald McDonald House Charities (RMHC).

"Uncle O’Grimacey is currently visiting all the way from Sham Rock, Ireland, touring the country with shakes in hand and spreading shamrock cheer," McDonald's said on Monday, March 17.

"And for this special Shamrock Shake Season, McDonald’s is donating $0.25 cents of every Shamrock Shake to RMHC through March 23.

"As he wraps up his nationwide tour, he couldn’t miss out on the most iconic St. Patrick’s Day celebration in the country – right here in Chicago!"

Indeed, Uncle O'Grimacey had the privilege of riding in a boat as the Chicago River was dyed green on Saturday, March 15 ahead of the city's annual St. Patrick's Day parade.

You can watch Uncle O'Grimacey cruising the green Chicago River here:

Uncle O'Grimacey's strange journey from Shamrock Shakes to the IRA

Uncle O'Grimacey was dreamed up by McDonald's back in the 1970s to help sell - you guessed it - Shamrock Shakes.

Some 20 years later, the US-based satirical publication The Onion made the - satirical - link between Uncle O'Grimacey and the IRA in its 1997 article "Sinn Fein Leaders Demand Year-Round Shamrock Shake Availability."

Uncle O'Grimacey managed to lay low for two more decades before he - and his IRA link - popped up in a 2017 article on PhillyVoice by Bryan Bierman.

"Although the character appeared in television commercials for a few years in the ‘70s and early ‘80s, Uncle O’Grimacey was let go shortly after because of his controversial ties to the IRA," Bierman wrote in his article about Shamrock Shakes.

Bierman's claim was later cited - and wildly embellished upon - in a 2021 piece on Odd Athenaeum. Screenshots of the article went on to circulate on social media, swiftly bringing Uncle O'Grimacey into the 2020s realm of Internet meme culture.

Last March, IrishCentral tracked down Bierman to ask him if he had proof that Uncle O'Grimacey had IRA ties or if it was just a joke.

"NO IT IS NOT TRUE," Bierman quickly replied with a cry-laughing emoji.

"I have been trying to clear Uncle O'Grimacey's name for some time," he added.

Indeed, Bierman shared with IrishCentral a video he recorded in March 2023 in hopes of clarifying the situation. In his video, he explains that he received a notification that his 2017 article was referenced in a March 2023 article posted on Boing Boing.

(As it happens, the Boing Boing piece was a step ahead of IrishCentral, making the connection between The Onion, Bierman's piece in PhillyVoice, and the 2021 Odd Athenaeum article.)

Bierman admitted in his video that he "100% made up" his 2017 line about Uncle O'Grimacey and the IRA, but that the Odd Athenaeum article "added more bulls--t." He also said he hadn't seen the 1997 satirical article from The Onion.

"It's weird that people added more information to it, which I guess is how fake news and this bulls--t starts," Bierman said, apologizing.

Bierman further told IrishCentral: "The article it was from was a goofy junk food review series I used to do and I just made that joke thinking it would be clearly a joke but I guess it wasn't that funny because it has spread over time.

"It's probably the most impactful thing I've ever written and I didn't even mean to!"

He continued: "What I guess happened was another website added more fake details to the story which made it spread.

"It's insane, when you search Uncle O'Grimacey on Google the next thing that comes up is IRA.

“I feel bad for what I've done.

"I have left comments on articles about it before but maybe they think I'm just a nut."

Bierman added: "Thank you for helping Uncle O'Grimacey, he didn't deserve that."