Obama unveiled a new ad jabbing Romney over his vow to cut the subsidy for US public television, home of Big Bird's stomping ground "Sesame Street" if he is elected on November 6.
"Mitt Romney knows it's not Wall Street you have to worry about, it's Sesame Street," the ad said, jokingly describing Big Bird as the "evil genius" towering over financial felons like Ken Lay and Bernie Madoff.
"Mitt Romney. Taking on our enemies, no matter where they nest," the announcer of the television ad, says pressing home Obama's contention that Romney, a former venture capitalist, would let Wall Street run wild.
Romney responded by feigning puzzlement about why Obama would dwell on such a triviality exactly four weeks before election day.
"These are tough times, with real serious issues. So you have to scratch your head when the president spends the last week talking about saving Big Bird," Romney said at a rally in Iowa.
Romney said in a debate in Denver last week that "I like PBS. I like Big Bird," but nevertheless pledged to cut the subsidy for the station as part of spending reductions he plans if he is elected president in November.
Obama did not pick up on the comment during his lethargic debate performance, but has since made Big Bird, who helped many Americans learn to read as tots, as a feature of his stump speech.
His spokeswoman Jen Psaki told reporters aboard Air Force One on Tuesday: "there is only one candidate in this race who is going to fight for Big Bird and Elmo and he is riding on this plane."
Psaki also made what the Obama campaign sees as a serious point about Romney's failure to provide concrete examples in the debate about what he would do to trim the US budget deficit.
"When Mitt Romney was given the opportunity to lay out how he would address the deficit his first offering was to cut the funding for Big Bird."
Sesame Workshop, maker of Sesame Street, said meanwhile it was a nonpartisan, non profit organization and had asked that the ad, which features footage of the furry Muppet, be taken down.
Psaki said the Obama campaign had received the request and was reviewing its options on the ad, which is running on national cable stations.