Howard Stern is biting the hand that feeds him. Stern, a judge on NBC's "America's Got Talent," slammed NBC's "Tonight Show" host Jay Leno following reports that Leno had taken a pay cut to save jobs after the network laid off about 20 staffers from his show.

"It's a smokescreen... Here's what it really means, and you can take this to the bank: Jay Leno is a scumbag," Stern said last week on his radio show. "He's a spineless maggot. Jay wanted to cut staff. He's embarrassed to do it. He didn't want to come off as a bad guy."

SODAHEAD SLIDESHOW: See the nastiest celebrity feuds.

The following day, Stern said he received a "threatening kind of comment" from an NBC executive who asked him to stop talking about Leno. But Stern refused to shut up. "I said, 'Do not tell me not to talk about Jay Leno.' I will f***ing talk about Jay for four hours if you tell me not to. I was done with Jay -- now I'm all fired up again.

"I love my job on 'AGT,' I love working for the people at NBC -- they've been nothing but wonderful," Stern continued. "But please don't tell me what to say. I'd rather leave than not talk about Jay Leno. ... It's fine. Fire me too."

PHOTOS: See the latest celebrity pictures to hit the Internet.

We get it, Howard. You really, really hate Jay Leno. From Stern vs. Leno to Joan Rivers vs. Rihanna, let us know: Who had the nastiest celeb feud?