President Donald Trump ridiculed Mayor Pete Buttigieg on Friday, describing him as Alfred E. Neuman, the cartoon icon from Mad Magazine.

“Alfred E. Neuman cannot become president of the United States,” he said when asked by Politico reporters about his thoughts on Buttigieg, the mayor of South Bend, Indiana who is now running for president.

Newman was first published in the magazine in 1956 and famously appeared as a write-in candidate for president on the cover.

.@MADmagazine display in Pomona Public Library reminds me: Did anyone today write in Alfred E. Neuman? pic.twitter.com/zQQeuFioVx — David Allen (@DavidAllen909) June 8, 2016

Newman is entirely fictional, but still gets some of the protest vote in recent presidential elections.

Buttigieg responded to the president, admitting that he had to Google the fictional character to figure out what the president was talking about.

“I’ll be honest, I had to Google that, I guess it’s a generational thing, I didn’t get the reference,” he told reporters on Friday night.

Ouch! Mayor @Pete Buttigieg responds to ⁦@realDonaldTrump⁩ slam that he is “Alfred E Neuman” —“I had to Google that..I guess it’s a generational thing.” pic.twitter.com/ZL11noISYL — Carla Marinucci (@cmarinucci) May 11, 2019

“It’s kind of funny I guess, but he’s also the president of the United States and I’m surprised he’s not spending more time trying to salvage this China deal,” he added.

Mad Magazine responded to Buttigieg on Twitter.

Who’s Pete Buttigieg? Must be a generational thing. — MAD Magazine (@MADmagazine) May 11, 2019

Trump also focused on Buttigieg’s last name during a campaign rally on Wednesday, pointing out the campaign’s effort to teach supporters to say “Boot-edge-edge.”