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(CNN) — The way Donald Trump tells it, he was watching television with corporate bigwigs at his golf course when an ad criticizing him popped up.

“They came in waves, one after another after another and it was brutal,” he said earlier this month after he won the Florida primary.

The GOP front-runner was witnessing what voters in states across the country have seen, a slice of the more than 53,000 anti-Trump ads, many of them courtesy of Republicans, according to data from the ad tracking firm Kantar Media/CMAG.

Altogether, the barrage has cost just shy of $67 million as of Tuesday.

The ads hit Trump seemingly from every angle: his past support for Democrats and Democratic views, his temperament and judgment, and his business use of eminent domain and bankruptcy. But as some Republicans brainstorm ways to disrupt Trump’s march to the GOP nomination, it is increasingly clear that the attacks have failed to stop Trump.

For much of the campaign, a super PAC supporting former Florida Gov. Jeb Bush led the ad campaign against Trump. Right to Rise USA spent at least $9.6 million on the effort, even running a rare two-minute long ad with a montage of some of Trump’s most controversial campaign moments. (The spot aired six times for New Hampshire voters, according to Kantar Media.)

But when Bush dropped out in February, Conservative Solutions PAC — a group supporting Sen. Marco Rubio of Florida — kicked into overdrive. At that point, it already spent around $3 million against Trump. But over the next month, it blasted out $16.7 million in anti-Trump ads, according to the Kantar Media data.

More than $7 million of that was an attempt to hold back Trump in Rubio’s home state of Florida; Trump’s 19-point win there ultimately knocked Rubio out of the race.

Now, the anti-Trump mantle rests with the remaining GOP candidates, Sen. Ted Cruz of Texas and Gov. John Kasich of Ohio. Cruz has spent about $3 million of his own campaign funds on anti-Trump ads, and groups supporting him have spent an additional $6.3 million. A group supporting Kasich has spent about $3 million on the airwaves.

There are also several super PACs that appear to be primarily focused on defeating Trump, rather than electing a different candidate; together those groups have so far spent about $12.5 million.

Here are some of the ways the groups have gone after Trump:

‘Reckless’

Trump is “erratic” and “unreliable,” says the anti-Trump ad that Kantar Media data shows has run more than any other spot against him.

Other spots call him a “reckless blowhard,” “impulsive” and a “phony conservative.”

Many of the ads against Trump criticize him as lacking the steadiness to handle dangerous times, unwilling to denounce groups like the KKK, and unable to hold back from hurling juvenile insults at his opponents.

A newly-released spot from the pro-Cruz group Our Principles PAC features women reading the derogatory words and phrases he has hurled at other women.

Not conservative

For ad makers trying to portray Trump as something other than a conservative, this line from Trump himself was pure gold: “In many cases, I probably identify more as a Democrat.”

It appeared in several spots, including one called “Trump Show” from a pro-Cruz group called Stand for Truth PAC that has aired nearly 1,500 times.

And there’s material linking him to Hillary Clinton, using soundbites praising her, his contributions to the Clinton’s charitable foundation and a photo of him and the former first couple.

Several ads also pointed out instances of Trump embracing tax increases, taking a pro-choice position on abortion and endorsing government-funded health care.

“First there was Hillarycare. … Then there was Obamacare,” one spot goes. “We can’t afford Trumpcare.”

Another: “Donald Trump is not a conservative because he’s extreme on abortion.”

And yet another opens with pictures of Clinton and Bernie Sanders: “Which presidential candidate supports higher taxes, national health care, and the Wall Street bailout?” Then Trump’s face appears. “It’s Donald Trump.”

Unscrupulous business dealings

Trump’s supporters see his experience in the business world as a key asset, while his opponents see shady practices and bankruptcies.

His use of eminent domain has come under intense criticism from Ted Cruz’s campaign.

“Trump bankrolled politicians to steamroll the little guy, a pattern of sleaze stretching back decades,” says the narrator in spot that calls out Trump’s attempt to seize an elderly woman’s home for his Atlantic City casino.

And in one of the most memorable ads this year, several kids shout “eminent domain” before bashing a dollhouse to bits.

Ads have also gone after Trump’s defunct real estate training program, calling it a “scam” and an “unlicensed illegal school.”

People who say they are former students have starred in some of these ads. Says one named Sherri: “America, do not make the same mistake that I did with Donald Trump. I got hurt badly and I’d hate to see this country get hurt by Donald Trump.”

A taste of the general election

It may be hard to imagine more lines of attack, but Clinton’s campaign trail criticism of Trump spotlights issues his Republican rivals haven’t highlighted in their ads: his positions on Muslims, undocumented immigrants and waterboarding.

The likely Democratic nominee has thus far spent about $3.5 million against Trump, according to Kantar Media, criticizing him as reckless.

“One of these Republicans could actually be president,” the narrator says in one spot. Then Trump appears and says, “I would bomb the s— out of them.”

It ran 1,643 times. But if Trump and Clinton do face each other in the general election, expect a lot more.