(JTA) — The Anti-Defamation League has added the internet meme Pepe the Frog, a cartoon character that has become a popular symbol for white supremacists, to its online hate database.

Images of the frog, variously portrayed with a Hitler-like mustache, wearing a yarmulke or a Ku Klux Klan hood, have proliferated in recent weeks in hateful messages aimed at Jewish and other users on Twitter, according to the ADL.

Pepe, which has been ubiquitous on the internet over the past decade, in the last year or so has become the flag bearer of the alt-right, which advances an insular conservatism favoring white people.

Earlier this month Donald Trump Jr., son of the Republican presidential nominee, posted to Instagram a movie poster parody of himself heroically grouped with Pepe and others deemed “The Deplorables.” Democratic nominee Hillary Clinton had said that half of all Donald Trump supporters are what she termed “deplorables.”

“Once again, racists and haters have taken a popular Internet meme and twisted it for their own purposes of spreading bigotry and harassing users,” said Jonathan Greenblatt, the ADL’s CEO. “These anti-Semites have no shame. They are abusing the image of a cartoon character, one that might at first seem appealing, to harass and spread hatred on social media.”

Other symbols have been added to the “Hate on Display” database in recent months, including the (((echo))) symbol, a triple parenthesis used by white supremacists to single out Jewish journalists and users on social media for harassment.