Last Week Tonight/HBO/Youtube John Oliver, the host of HBO's "Last Week Tonight," set his sights during Sunday night's episode on the Republican plan to repeal and replace the Affordable Care Act, the healthcare law better known as Obamacare.

The HBO political commentator and comedian broke down the major parts of the GOP's replacement plan and railed against it.

Oliver pointed to key points from a Republican fact sheet that went out to House GOP members last week. He broke down various parts of the proposal, from high-risk pools to Medicaid block grants. He said coverage was likely to be lacking, citing new Health and Human Services Secretary Tom Price's plan to replace the ACA.

"Tom Price once proposed a tax credit of $1,200 for people aged 18 to 35 and $3,000 to people 50 and up, which is roughly a third of the cost of the most bare-bones plans on the market today," Oliver said. "A tax credit that small helps cover your health insurance the way a thong covers your dad's a-- — it doesn't — and there's something fundamentally wrong about that."

Oliver also called out the lack of detail in the Republican guidelines, citing the use of a placeholder at the end of one draft of a bill. (The bill is not finalized, however.)

"If you need any more proof of how unprepared Republicans are right now, let me show you one of the draft bills they circulated," Oliver said. "It is just seven pages long and it end abruptly with the word 'placeholder.'"

Oliver concluded by saying the timeline for a Republican replacement was growing shorter, since insurance companies must submit plans for their 2018 exchange coverage in April.

"Insurers are going to need an answer soon, so ticktock motherf------ because you don't get to placeholder your way out of this one again," Oliver said.

Watch the full segment here: