U.S. Senate candidate Chris Murphy dismissed his opponent Linda McMahon’s most recent attack, calling him a “funny guy,” as a desperate joke.

Murphy, a Democratic Congressman, is running against McMahon, a Republican former wrestling CEO, for retiring U.S. Sen. Joe Lieberman’s seat.

McMahon’s new ad rehashes some of the issues her campaign has been stressing over the last few weeks like alleging Murphy received a special loan deal from Webster Bank and skipped legislative committee hearings. The ad released Monday shows pictures of Murphy laughing with a laugh track in the background.

But the video also points to stock footage of a submarine used in one of Murphy’s television ads, which it says is actually a Norwegian sub, not a Connecticut made ship. Murphy used the footage to tout efforts to help the Electric Boat plant in Groton. Murphy voted twice against defense spending bills which included money for contracts with Electric Boat.

“Uhhhhhhhh, Chris?” the narrator says. “That submarine in your commercial? It’s from Norway, not Groton. Chris Murphy is a funny guy.”

Asked Monday if he wanted to comment on the submarine footage, Murphy said, “I almost don’t.”

“I mean what a joke. Linda McMahon is so desperate to not talk about the actual issues in this race that she’s sending out press releases about stock photos in TV ads. You know, this is a sign that Linda McMahon knows she’s losing this race . . . she’s reduced to talking about images in a TV ad,” Murphy said.

The Ula class of submarine shown in the ad was built in Germany. The class only has six submarines.