Donald Trump's best faces of the Republican debate

Tuesday night's Republican debate found businessman Donald Trump once again under attack from several of his Republican rivals. And while they were talking about him, he let his face tell the audience exactly what he thought of their barbs.

Sen. Rand Paul, R-Kentucky and former Florida Gov. Jeb Bush made the most aggressive attempts to go after Trump and elicited the most emotive responses from the businessman.

At one point, Paul questioned Trump's proposal to shut down "areas" of the Internet in places where it is being used to spread terror.

"If you're going to close the Internet, realize, America, what that entails. That entails getting rid of the First amendment, OK? It's no small feat," Paul said.

Trump made a dismissive noise, narrowed his mouth into a line, and waved Paul away. Then he shook his head and sported a look of incredulity.

Paul went on to question Trump's pledge to go after the families of terror suspects.

"When you ask yourself, whoever you are, that think you're going to support Donald Trump, think, do you believe in the Constitution?"

At that moment, Trump's face recalled that of U.S. gymnast McKayla Maroney when she twisted her mouth into a half-scowl and scrunched-up her nose, after she unexpectedly fell on a vault and had to settle for the silver medal at the London Olympics.

While Bush went on the attack over Trump's call to crack down on families of terrorists -- calling it an idea that showed the "lack of seriousness" and "just crazy" -- Trump shook his head, closed his eyes and raised his eyebrows in disbelief.

"Two months ago Donald Trump said that ISIS was not our fight. Just two months ago, he said that Hillary Clinton would be a great negotiator with Iran," Bush continued.

Trump pursed his lips and looked off into the distance skeptically.

But at least one mention from another candidate drew a more positive reaction. Talking about immigration, Texas Sen. Ted Cruz said, "We will build a wall that works, and I'll get Donald Trump to pay for it."

Trump smiled and patted him on the shoulder.