‘Justice for O’Grimacey’: The Shamrock Shake is back—and so are the wild rumors about Uncle O’Grimacey

A long-lost McDonald’s character by the name of Uncle O’Grimacey is back—and so is the urban legend surrounding his disappearance.

Every year, McDonald’s puts its Shamrock Shake back on the menu in time for St. Patrick’s Day. The fan-favorite limited item has been around for over 50 years, but what not everyone remembers is that it was once promoted by a character brought around just for the occasion: Uncle O’Grimacey.

Who is Uncle O’Grimacey?

Uncle O’Grimacey had his debut in 1975, five years after the Shamrock Shake itself was introduced to the world.

Within the MCU (McDonald’s Commercial Universe), this fuzzy green blob of a creature is uncle to Grimace, a point made abundantly clear both by their respective appearances and names. Besides being green, Uncle O’Grimacey’s appearance is defined by his green hat, green vest with shamrock buttons, and, at times, a fashionable cane.

“This Shamrock Season celebration came to life when Grimace stumbled upon his family’s original Shamrock Shake recipe,” reads the press release announcing his return. “That discovery sparked Grimace to reconnect with his vibrant, joyful, and generous uncle, Uncle O’Grimacey.”

After his debut in ’75, the character made regular appearances in McDonald’s advertisements to promote the St. Patrick’s Day shake for about a decade before fading out of the public eye.

What is the controversy surrounding Uncle O’Grimacey?

McDonald’s has rotated various characters in and out of its ads for decades. One disappearing for a while — or even forever — isn’t that big of a deal. But with Uncle O’Grimacey, there’s a little more to the story, or so the story goes.

Legend has it that the character was disappeared by McDonald’s following an incident in Philadelphia in either the late 1970s or early 1980s during which an actor dressed as him made public statements supporting the IRA (Irish Republican Army).

The origins of the rumor are unclear. Some have suggested the first known link between Uncle O’Grimacey and the IRA comes from a 1997 article from The Onion about the IRA demanding Shamrock Shakes be available year round. The satire piece refers to the character as “the most radical member of the Grimace family” and quotes him as saying, “Release the shakes to us at once, or the lives of your children will be forfeit.”

There was also a brief joke about Uncle O’Grimacey having IRA ties in a 2017 PhillyVoice article. IrishCentral tracked down its writer, Bryan Bierman, in 2024, who expressed concern he may be responsible for the legend and said he’s “been trying to clear Uncle O’Grimacey’s name for some time.”

Everyone is making the same IRA jokes

Regardless of where the legend of Uncle O’Grimacey originates, or whether it’s based in fact or fiction, it has persisted. And that means his sudden return after 40 years or so has everyone on social media making the same joke about where he’s been all this time.

Uncle O’Grimacey was just released from prison after his sentence for bombing British soldiers. https://t.co/3QLCe7L0a5

— Shane (@BokononsProphet) February 4, 2025

don’t ask why Uncle O’Grimacey has been away for so long https://t.co/87BgzxbxPw pic.twitter.com/uK88V9gx9p

— sarge (@sarge__msu) February 5, 2025

happy to see uncle o’grimacey getting acclimated with modern technology after doing a bid for possession of molotov cocktails and automatic weapons https://t.co/GbHNPjnDll

— Kyle Schaefer (@kschaef) February 5, 2025

Never forget Uncle O’Grimacey’s resilience during The Troubles. https://t.co/PlCkmE79RF pic.twitter.com/swNKLC9sZb

— Based Buc-ee (@Natnl_Disgrace) February 4, 2025

How me and the homies pulling up for the Uncle O’Grimacey Cup https://t.co/rcCpv6Zkx8 pic.twitter.com/iFXu59tckG

— tyler (@thatdudeTB) February 4, 2025

BREAKING: Uncle O’Grimacey delighted to be working for McDonald’s again despite his involvement in the 1996 London Dockland Bombings pic.twitter.com/eKxYPG8ZRV

— Not the RTÉ News (@notthertenews) February 5, 2025

Fixed Uncle O’Grimacey for accuracy. https://t.co/byKgJcRwOk pic.twitter.com/aUkFeO8IYw

— Mike Beauvais (@MikeBeauvais) February 4, 2025

Uncle O’Grimacey after a one too many Shamrock Shakes https://t.co/eKUtSFTLt3 pic.twitter.com/d5mtuSVAG3

— Griff (@Griffa11) February 5, 2025

you would never know that uncle O’Grimacey helped plant the bomb that took out Mountbatten in ’79 pic.twitter.com/jSdyRCNjLm

— Chalbs™ (@Aetherfl0w) February 5, 2025

What’s next for Uncle O’Grimacey?

There’s no word yet as to how long Uncle O’Grimacey will get to stick around this time, but for the time being, McDonald’s is celebrating by selling merch branded with the long-lost character.

They’re also donating $0.25 to their Ronald McDonald House Charities for each Shamrock Shake purchased between February 10 and March 23.

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