Jimmy Kimmel is firing back at Sen. Bill CassidyWilliam (Bill) Morgan CassidyGOP senators introduce resolution endorsing ICE Lawmakers pitch dueling plans for paid family leave New push to break deadlock on paid family leave MORE after the Louisiana Republican said the late-night talk show host doesn't understand the Senate GOP's latest attempt to repeal and replace ObamaCare.

"Oh I get it, I don't understand it because I'm a talk show host," Kimmel said during his opening monologue late Wednesday. "Then help me out. Which part don't I understand? The part where you cut $243 billion dollars from federal health-care assistance? Am I not understanding the part where states would let insurance companies price you out of coverage for having pre-existing conditions?"

“Could it be, Sen. Cassidy, that the problem is that I do understand and you got caught with your G-O-Penis out. Is that possible?” Kimmel asked.

The comedian one night earlier had lambasted Cassidy over the GOP's last-ditch attempt to repeal the Affordable Care Act, spearheaded by Cassidy and fellow Sen. Lindsey GrahamLindsey Olin GrahamKelly lobbied Republicans to rebuke Trump after Putin press conference: report Senate weighs new Russia response amid Trump backlash Trump stuns the world at Putin summit MORE (R-S.C.). Cassidy previously pledged on Kimmel's show that any bill he voted for would pass the "Jimmy Kimmel Test," which was inspired by Kimmel's son, who was born recently with a congenital heart defect.

Kimmel's harshest criticism in his latest monologue was aimed squarely at Brian Kilmeade, however. The "Fox & Friends" host earlier Wednesday accused Kimmel of being the latest liberal Hollywood celebrity “pushing their politics on the rest of the country.”

“This is a guy, Brian Kilmeade, who, whenever I see him, kisses my ass like a little boy meeting Batman,” Kimmel told his audience Wednesday.

“Oh, he’s such a fan. ... He follows me on Twitter. He asked me to write a blurb for his book, which I did. I don’t get anything out of this, Brian, you phony little creep," Kimmel added. "Oh, I’ll pound you when I see you.”

He ended his monologue with another impassioned plea for Americans to call their senators and representatives over the bill, which the GOP could vote on next week.

“This is why things like this keep happening, because we don’t do anything about them,” Kimmel said.

“So please stop texting for five seconds and make a phone call. Especially call these senators. ... It really does make a difference.”