In horror movie fashion, they pretend in their video clips to writhe in agony in a purple puddle and suffer gruesome fake deaths. The Grimace shake has “claimed the lives” of internet celebrities like Zach King and Brent Rivera as well as Lily, the dog of actress Courteney Cox. 

The limited-time Grimace birthday meal, which includes the vanilla-berry-flavored milkshake, debuted on June 12, in honor of the purple mascot’s birthday. (Apparently, he’s 52 years old.) 

Shortly after, the graphic and bizarre TikTok trend was born, with the hashtag #grimaceshake getting 2.9 billion views on TikTok, and helping boost McDonald’s second-quarter sales over 10% in the U.S. and nearly 12% globally, the company said Thursday. 

For the record, the fast-food chain also cited its chicken menu items—particularly the Chicken McNuggets—and new digital customer-experience offerings like the “Frequent Fryer Program” as helping to lift revenue. 

“The McDonald’s brand has never been stronger and I remain inspired by the ability of the McDonald’s System to create cultural conversations and develop industry-leading innovations,” Chris Kempczinski, McDonald’s CEO, said in a statement. 

Grimace breaks his silence

McDonald’s responded cheekily to the dark trend on June 27 when Grimace tweeted on the McDonald’s account: “meee pretending I don’t see the grimace shake trendd.” In a LinkedIn post on July 12, Guillaume Huin, McDonald’s social media director, denied that the company had any part in creating the viral phenomenon.

“This was a level of genius creativity and organic fun that I could never dream about or plan for—it was all from the fans, and the fans only, and the initial spark came from Austin Frazier,” Huin wrote, referring to the TikToker who started the trend with a 10-second video that now has over 3.6 million views. 

There is no apparent meaning behind TikTokers faking their deaths after sipping the milkshake. But what would normally be considered bad public relations—people pretending your product kills them—defied the norm and became a PR bonanza. At the very least, people were buying Grimace shakes, if not to drink them, then to be part of the trend.

Huin credited the success to the “brilliant creativity, unfiltered fun, peak absurdist Gen Z humor” and “the way a new generation of creators and consumers play with brands.”

When asked for comment, a McDonald’s spokesperson directed Fortune to the company’s earnings release and an earnings summary posted on its website.  

‘Peak absurdist Gen Z humor’

Grimace, the best friend of Ronald McDonald, made his debut in a 1971 commercial. He is an amorphous purple blob with short arms and legs that some speculate is the embodiment of a milkshake or a taste bud.

“Grimace is from Grimace Island and comes from a huge family (including his Grandma Winky, aunts Millie and Tillie and his Uncle O’Grimacey!),” McDonald’s told NBC’s Today show.

But Grimace isn’t the only unconventional mascot that’s taken off on social media. Language-learning app Duolingo has also used Gen Z’s absurdist humor to its advantage.

Duolingo’s mascot, a green owl named Duo, has become a TikTok personality with over 7.2 million followers. The videos range from Duo’s undying love for pop star Dua Lipa (even proposing to her outside of Madison Square Garden), to veiled threats against Duolingo users if they skip their daily lesson with phrases like “Spanish or vanish.”

The Grimace shake’s virality was unexpected, and Huin acknowledged that.

“If you think we planted the grimace shake trend, thank you. So much. But you think way too highly of us,” Huin wrote.