Republican presidential candidate Ted Cruz attempted to make a joke out of rival candidate Donald Trump raising questions in a recent interview over the Texas senator’s birth in Canada, and whether it will become a liability if he becomes the GOP’s nominee.

In an interview Tuesday with The Washington Post, Trump said Cruz’s Canadian birthplace and previously holding a double passport was “very precarious.”

“Republicans are going to have to ask themselves the question: ‘Do we want a candidate who could be tied up in court for two years?’ That’d be a big problem,” Trump told The Post. “It’d be a very precarious one for Republicans because he’d be running and the courts may take a long time to make a decision. You don’t want to be running and have that kind of thing over your head.”

He added that the Cruz’s birth in Canada was something that “a lot of people are talking about.”

Cruz responded to Trump’s comments on Twitter later Tuesday by referencing an episode of the sitcom “Happy Days,” where the character Fonzie jumps over a shark on water skis, equating it to the campaign “jumping the shark.”

Trump has ramped up his attacks on Cruz since the Texas senator sprinted ahead of the billionaire businessman in some opinion surveys in early-voting Iowa.

Cruz was born in Canada but his mother is a U.S. citizen. He has renounced his Canadian citizenship.

Trump was one of the loudest voices questioning whether President Obama was born in Kenya and thus not eligible to be U.S. president. Obama is an American citizen; his father was Kenyan, his mother American.

Previous foreign-born Americans — notably Republicans John McCain and George Romney — have run for president with some mention, but no serious challenges, of their eligibility.

The comments mark a reversal for Trump, who in September downplayed Cruz's birthplace in an interview with ABC.

"I hear it was checked out by every attorney and every which way and I understand Ted is in fine shape," he told the network then.

But Trump has been ratcheting up his attacks on Cruz in recent weeks.

Trump first unleashed a verbal assault on Cruz in December at an event in Des Moines where he questioned Cruz's evangelical faith.

"I do like Ted Cruz, but not a lot of evangelicals come out of Cuba," he said of the country where Cruz's father, an evangelical preacher, was born.

The Associated Press contributed to this report.