President Trump widened his attack on potential Democratic challengers for the 2020 presidential election today, likening South Bend, Indiana, Mayor Pete Buttigieg to Alfred E. Neuman, the gap-toothed “idiot kid” character made famous by satirical MAD Magazine, which was a popular publication predominantly among young readers from the 1950s-1980s.

The freckle-faced idiot kid with a dopey smile made his debut as a write-in candidate for president in 1956, and became the magazine’s mascot and icon.

Trump told Politico magazine on Friday, “Alfred E. Neuman cannot become President of the United States,” during a 15-minute telephone interview when asked what he thought of the 37-year-old challenger.

Buttigieg, who is the first significant openly gay presidential candidate, and one of the first gay mayors of a U.S. city, which also includes Long Beach, California’s Robert Garcia and others, admitted ignorance regarding the magazine character when asked how he felt about the reference by Politico while in San Francisco on Friday.

Buttigieg’s response included a thinly veiled slight at Trump’s relatively advanced age.

“I’ll be honest, I had to Google that. I guess it’s a generational thing,” he said.

Buttigieg suggested the president likely had more important matters to attend to, including failed trade talks with China that may result in an increase of tariffs on Chinese imported goods as high as 25%.

This is not Trump’s first barb aimed at Buttigieg. The relatively new potential challenger has received considerable and flattering press coverage recently, which has catapulted him into contender status.

As new candidates have emerged and received press attention, Trump seems to attribute a pet name for them. When former Vice President Joe Biden entered the race, the president referred to him as “Sleepy Joe,” and "not going to be able to do the job."