One of the Republican National Convention speakers would like to rub his testicles on your mother’s face—that is, if you happen to be Twitter user @Grateyfratez.

Dana White, who heads the mixed-martial arts league Ultimate Fighting Championship and sometimes tweets about his balls, was just announced as one of the speakers at the Republican National Convention in Cleveland. His appearance is part of Trump’s effort to recruit sports stars and celebrities for the event. And while White certainly brings athletic cred, he could also be a wee bit of a liability, given his history of taking to Twitter to direct sexist and violent threats at his critics.

Perhaps his most eyebrow-raising threat was directed at @Grateyfratez—himself no paragon of congeniality—a few days after the egg account tweeted that White looks like “an emo, bald Ellen Degeneres.”

“I’m gonna rub my nuts on ur moms face!!!!” White replied .

Donald Trump loves to inveigh against the evils of political correctness. And perhaps nothing is less politically correct than saying one plans to teabag a stranger’s mother. The uncharitable quip is very much in character for White. Over the years, he has displayed a fondness for criticizing Twitter users’ mothers, calling people “clown shoes,” and suggesting that his critics listen to John Mayer—or worse.

“bro ur name is OMG lady gaga!?” he tweeted at the now-defunct account @OMG_LadyGaga on Feb. 13, 2011. “LMFAO you should be beat with a fuckin stick and kicked in the nuts repeatedly.”

He recommended a similar fate for one of the judges of a June 11 fight, noting that he “should be BEAT WITH A STICK!!!!!!!!”

He also said that one user’s mom was “so fat she got baptized at seaworld!!!”

His tweets also indicate a high level of interest in the testicles of UFC fighter Fedor Emelianenko.

“ur a jackass get fedors nuts outta ur mouth,” he tweeted at user @PJ2661gambler on Valentine’s Day of 2011.

On July 1, 2010, he posited that user @fjbar75 “will have to remove fedors nuts from his tonsils!!! Boooooo hooooooo fedorrrrrrrrr!”

He sometimes took a protective stance to Emelianenko’s genitalia.

“stop swingin on fedors nuts and get your own life you loser!” he wrote to user @RUSSIAandSERBIA on June 30, 2010.

He was less protective of other men’s balls.

“I hope you get kicked in the nuts. Twice!!” he tweeted at one now-defunct account on May 25, 2010.

He expressed the identical sentiment to another now-defunct account on June 25, 2011.

“I hope you get kicked in the nuts twice today,” he wrote .

White also has invested a significant amount of time in calling users “pussy” or “puss” —sometimes coupled with the recommendation that they “go follow John Mayer.”

And he’s in the habit of suggesting a variety of other sources of entertainment for critics of the UFC. He suggested to four separate users that they watch The Vow, a romantic 2012 film starring Rachel McAdams and Channing Tatum, instead of watching UFC programming. And he recommended that another Twitter user , who called UFC “trash,” rent The Notebook. He has also suggested that multiple users critical of his statements should instead follow the boy band One Direction.

“I cuss you better follow One Direction if you don't want cussing” he announced on Dec. 31, 2015.

He also weighed in on interesting internet debates, including whether or not Hitler was a “hater.”

“Lol hitler wasn’t a hater u idiot,” he tweeted on Oct. 14, 2010 . “Hitler was a twisted sick fuck!!! Big difference.”

Sometimes, however, White has opted to disengage from his critics.

“I’m going on a blocking spree today,” he announced on July 12, 2012. “Who’s first fuckers?”