Donald Trump Jr. borrowed an analogy popular among anti-immigrant activists and white nationalists for his meme likening Syrian refugees to poisoned Skittles.

In a Monday tweet, the GOP nominee’s son suggested that accepting large numbers of refugees from the war-torn country posed the same risk as eating from a bowl of the rainbow-colored treats in which three of the candies “would kill you”:

This image says it all. Let’s end the politically correct agenda that doesn’t put America first. #trump2016 pic.twitter.com/9fHwog7ssN — Donald Trump Jr. (@DonaldJTrumpJr) September 19, 2016

Detractors quickly pointed out that the meme not only belittled the plight of millions of refugees but wildly overestimated the likelihood of being killed by a refugee. The libertarian Cato Institute put the odds of an American being murdered in terrorist attack carried out by a refugee at 1 in 3.64 billion per year.

Despite being branded with the Trump-Pence 2016 logo, the image was also not original to the Trump campaign. The meme has a long, weird shelf life on the Internet and is often used to describe the influence of a small population within a larger group. A variation involving M&Ms was actually used back in 2014 by some feminists on social media to push back on the “Not all men” defense against accusations of misogyny.

In its ugliest form, the analogy has roots in Nazi propaganda. As Raw Story and The Intercept pointed out, anti-Semitic newspaper publisher Julius Streicher, who was later hanged at Nuremberg, wrote a children’s book in 1938 that compared Jews to poisonous mushrooms.

“Just as a single poisonous mushrooms can kill a whole family, so a solitary Jew can destroy a whole village, a whole city, even an entire Volk [nation],” the book, “Der Giftpilz,” or “The Toadstool,” read, according to The Intercept.

The embrace of this ethnically-tinged version of the analogy took root on white nationalist blogs and fringe message boards in 2015, ticking upwards after the November terrorist attacks in Paris. Versions similar to the one Trump Jr. posted, also often featuring M&Ms, have circulated widely in those venues.

On ex-army.blogspot.com, self-described “libertarian nationalist” Matt Bailey compared refugees to “hand grenades” in a barrel of apples in a meme posted in November. A blog post from the same month on anti-immigrant website Virginia Dare used the “great” M&M metaphor to make the case that Virginia should not accept Muslim refugees. White nationalist site therightstuff.biz described it as an “infamous” reference last fall, and far-right fringe site The Burning Platform shared a visual depiction of it borrowed from an alt-right Twitter user:

Elected officials adopted the comparison, too. In an appearance on MSNBC last November, former Arkansas governor and current Trump supporter Mike Huckabee compared refugees to a large bag of peanuts in which a handful were “deadly poisonous.”

Trump Jr.’s Monday tweet is just the latest hat tip from the Trump campaign to white nationalists and the alt-right.

The Republican nominee’s son came under fire just last week for sharing a photo featuring Pepe the Frog, a cartoon figure that has become a mascot of sorts for white nationalists online. Trump Jr. also followed up the Skittles tweet Tuesday by sharing a link to an article about Muslim immigrants raping American women, which is a pet concern among this fringe group.

Trump himself has retweeted posts from users with the handles like @WhiteGenocideTPM on multiple occasions.

The continuing, outsized influence of white nationalist Internet users on Trump and his inner circle shouldn’t come as a surprise. Trump made his campaign’s synthesis with that fringe group official when he hired Breitbart News chairman Steve Bannon as his campaign CEO in August. Bannon has referred to Breitbart, which pumps out pro-Trump stories daily, as a “platform for the alt-right.”

The campaign’s anti-refugee rhetoric has upset at least one person involved in the creation of the Skittles meme: the man who photographed the bowl of the candy used in the image. In a remarkable turn of events, photographer David Kittos revealed to the BBC on Tuesday that he was himself a refugee and that the photo was used without his permission.

“In 1974, when I was six-years old, I was a refugee from the Turkish occupation of Cyprus so I would never approve the use of this image against refugees,” Kittos said.

“I don’t support his politics,” he added of Trump.

This post has been updated.