Marco Rubio said Wednesday he's "not entirely proud" of his personal attacks on Donald Trump and wouldn't have launched them if he could do things over again. "In terms of things that have to do with personal stuff, yeah, at the end of the day it's not something I'm entirely proud of. My kids were embarrassed by it, and if I had to do it again I wouldn't," he said during an MSNBC town hall. Rubio's sudden shift to aggressively attacking Trump one week before the Super Tuesday primary contests saw the candidate mock Trump on the debate stage and during nearly every one of his stump speeches following. The attacks took a personal turn, with Rubio making fun of Trump's tan, his hair and ultimately the size of his hands — a veiled jab at Trump's manhood — at a rally shortly before voters went to the polls that week. The strategy won him wall-to-wall media coverage but did little to cement Rubio as the anointed alternative to Trump. Indeed, it appears to have hurt him, as he struggled to overcome Ted Cruz during the Super Tuesday contests and his support has since cratered, resulting in disappointing finishes in primaries across the nation over the past week. Some Republicans have criticized Rubio for "damaging the image of the Republican Party," as major Republican donor Fred Malek put it on MSNBC this week. Rubio's comments Wednesday were an implicit acknowledgment that the strategy didn't work, and he has since shifted away from personal attacks on Trump in favor of more policy-focused fare. But he insisted that it was "appropriate" to point out that Trump is "portraying himself as something he's not," a central focus of his argument against the GOP frontrunner. RELATED: Marco Rubio's campaign is on life support Trump has been dismissive of Rubio's attacks, telling reporters at a press conference Tuesday that "hostility works for some people — it doesn't work for him." But on MSNBC Wednesday morning, he was asked about the possibility of a Rubio pick. "Sure, sure and he's got talent. I just don't want to say that yet," Trump said. Rubio, however, insisted at the MSNBC town hall Rubio said he had no interest in playing second fiddle for Trump or any other GOP candidates. "I'm not looking to be anyone's vice president," Rubio said. Pressed directly is he would tell Trump "no" if asked to being his running mate, Rubio responded, "absolutely." This story originally appeared on NBCNews.com.