Nikki Haley is stepping up her attacks on Donald Trump‘s age — this time at his own rally in South Carolina.

The Haley campaign on Saturday will parade a mobile billboard around the Myrtle Beach area, including by Trump’s rally in Conway, where the former president will appear for the first time this year in the state ahead of South Carolina’s Feb. 24 GOP presidential primary.

Haley’s latest trolling attempt, first confirmed to POLITICO, involves the campaign playing a video featuring clips of Trump and President Joe Biden trailing off and otherwise appearing confused during recent public remarks. That’s after Haley declared on Friday that Biden, 81, and Trump, 77, would be using the White House as a “taxpayer-subsidized nursing home,” and that Trump is suffering from “mental deficiencies.”

The issue of candidates’ age, long a feature of the presidential campaign, took on heightened significance when the special counsel investigating Biden’s handling of classified documents issued his report on Thursday on the matter. While finding no criminal charges were warranted, the report presented a damaging portrait of Biden’s mental acuity.

Horry County, the site of Saturday’s Trump rally, is a conservative stronghold where Trump won nearly half the vote in a still-crowded 2016 presidential primary — and some of the least fertile ground for Haley in this month’s contest. Her campaign’s decision to send a roving billboard truck into the heart of MAGA country underscores Haley’s brash approach of rebuking Trump now that the race is a head-to-head match — and as she remains far behind.

Her recent offensive against Trump, after months of offering only tepid criticism of the front-runner, comes as the former South Carolina governor trails Trump by a massive margin in her home state. Trump racked up top Republican endorsements early in the state and has kept a firm grip on the conservative base in South Carolina.

Haley and her top campaign aides have said she plans to stay in the primary race for the long haul — regardless of her South Carolina performance — and that she has no reason to bow out before voters in Super Tuesday states cast ballots in early March.

Since announcing her bid a year ago, Haley has called for a new, younger leader for the party and country. But she has ramped up her criticisms of Trump lately, including during a segment on “Saturday Night Live” last weekend.

Trump has likewise gone after Haley, posting on Truth Social on Friday a 2012 video of Haley at a Mitt Romney rally mistakenly praising then-President Barack Obama, instead of Romney, and criticizing her for taking campaign money from Democratic donors.

“Donald may be suffering from memory issues,” Haley, who is 52, posted in response, asking whether Trump forgot that he had donated to Democratic politicians.

Haley on Saturday is embarking on a bus tour to stops in rural South Carolina.