For the second straight day, Rick Santorum’s presidential campaign is making waves with a television ad.

Santorum’s newest ad, called “Rombo,” features a Mitt Romney lookalike — easily identifiable by his fancy clothes and trademark haircut — stalking through an abandoned warehouse with a machine gun and attempting to shoot mud at a cardboard cutout of Santorum.

The ad concludes with “Rombo” covered in mud from his own gun, and the ominous warning that “in the end, Mitt Romney’s ugly attacks are going to backfire.”

Here’s the ad:

A transcript of narration is below, courtesy of Politico:

“Mitt Romney’s negative attack machine is back, on full throttle. This time, Romney’s firing his mud at RICK SANTORUM. [Sound of gunfire.] Romney and his super PAC have spent a staggering 20 million … attacking fellow Republicans. Why? Because Romney’s trying to hide from his big-government Romneycare, and his support for job-killing cap-and-trade. And in the end, Mitt Romney’s ugly attacks are going to backfire.”

As MSNBC’s First Read points out, the ad is significant because it represents a powerful response to Romney’s super PAC spending — something that Newt Gingrich never had in Iowa and Florida. Given that he is currently being outspent 29 to 1 in Michigan, Santorum will need an effective weapon to combat Romney’s financial advantage.

It appears that his campaign believes “Rombo” could be that weapon. The size of the ad buy is unknown, but a Santorum aide told Politico “everyone in Michigan will see it.”