"Real Time" host Bill Maher returned Friday night after a holiday break and weighed in on potential witnesses in the Senate impeachment trial of President Trump, including the possibility of former Vice President Joe Biden and his son Hunter Biden being brought in to testify -- as well as Rudy Giuliani associate Lev Parnas.

Maher said that Democrats who've been pushing for witness testimony at the trial -- from the likes of former national security adviser John Bolton, for example -- could find themselves facing unintended consequences.

"How about this question: Could it backfire, witnesses?" Maher asked during the show's panel segment. "Because then [doesn't] Trump get to call Biden and his ne'er-do-well son?"

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Maher then blasted Biden for not having a better explanation for his son's ties to the Ukrainian company Burisma.

"Biden needs a better answer about his son than, 'I can do more push-ups than you,' and 'I'm going to beat you up,'" Maher said.

He then recalled the 2004 presidential election, when Democratic nominee and "war hero" John Kerry was transformed into a "war criminal," and Republican incumbent and "draft dodger" George W. Bush was transformed into a "war hero."

"If this gets to a trial and they call Biden and his son, trust me, Biden and his son and Ukraine will be the bigger scandal," Maher insisted.

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Later, Maher slammed Parnas, who made explosive claims this week during interviews on MSNBC and CNN, claiming Trump had direct knowledge of efforts to withhold U.S. aid from Ukraine in exchange for an announced investigation into the Bidens.

"He's not credible," Maher said of Parnas. "I believe him actually ... but he left a note to himself that said, 'Get Zelensky to announce that the Biden case will be investigated.' To himself! It's like a bank robber writing a note, 'Remember to rob bank.' It strikes me as suspicious that you'd do that."