But also showed off her singing skills when Fallon brought up the fact that she sometimes sings made up songs to her grandkids and her dogs, Max and Snickers. "I don't wanna put you on the spot," Fallon said.

"Wanna hear? You want me to hum a bar or two?" Fiorina offered. "This is a song in four verses, I'll only give you one. Ready?"

To the tune of 50's hit "Rock Around the Clock," she gave the audience a sneak peak of the Snicker's song that she sings for one of her two dogs: "My name's Snick, and I'm lazy. Please don't take a walk with me. I'd rather stay right here at home instead. I want to lie back down in my nice, warm bed. My name's Snick and you're gonna have to carry me." A seemingly shocked but entertained Fallon bopped along while the audience clapped to the beat and cheered.

Many candidates have used the late night stage to soften their image. Former President Bill Clinton famously played the saxophone on "The Arsenio Hall Show" in 1992, and Fiorina rival Donald Trump used it to poke fun at himself earlier this month. And as Fallon reminds, this is a show where "silly" lives.

But it wasn't all a song and dance on Monday night in New York City. Fallon also questioned Fiorina on the hot-button topic of Muslims in elected office, an issue popularized by a questioner at a Donald Trump town hall late last week and recently weighed in upon by another Republican front-runner, Dr. Ben Carson.

Carson told NBC's Chuck Todd on Meet the Press on Sunday, "I would not advocate that we put a Muslim in charge of this nation. I absolutely would not agree with that." To which Carly responded Monday evening: "I think that's wrong."