Donald Trump has a lot to say about his Republican opponents.

The 2016 contender has been quick to jab his fellow candidates, mocking Marco Rubio's never-ending thirst and dismissing Rand Paul as someone who shouldn't even be on the debate stage.

Scroll through to see some of the insulting things that he's said about the GOP presidential hopefuls over the course of his campaign.

Donald Trump on Ted Cruz

Donald Trump took aim at Ted Cruz on

Donald Trump took aim at Ted Cruz on "Fox News Sunday" on Dec. 13, calling the Texas senator a "maniac" who doesn't have the "right temperament" to be president.

"You look at the way he's dealt with the Senate, where he goes in there frankly like a little bit of maniac," he said. "You're never going to get things done that way. ... You can't walk into the Senate and scream and call people liars and not be able to cajole and get along with people."

(Credit: AFP / Getty Images / Nicholas Kamm)

Donald Trump on Ben Carson

Donald Trump compared Ben Carson's

Donald Trump compared Ben Carson's "pathological temper" to child molestation in a Nov. 12 interview on CNN.

Trump told CNN's Erin Burnett that Carson's 1990 autobiography, "Gifted Hands," says that Carson has a "pathological temper." He then said that people who have pathological tempers are incurable, like people who molest children. "You don't cure these people," he said. "You don't cure a child molester. There's no cure for it. Pathological, there's no cure for that."

Read more on Trump's remarks.

(Credit: Getty Images / Frederic J. Brown)

Donald Trump on Marco Rubio

Donald Trump has mocked Marco Rubio for sweating

Donald Trump has mocked Marco Rubio for sweating and drinking a lot of water -- most notably during his 2013 State of the Union rebuttal.

"Rubio, I've never seen a young guy sweat that much," Trump said at an appearance in September. "He's drinking water, water, water, I never saw anything like this with him with the water."

Trump took the mockery a step further in October when he sent Rubio 24 bottles of water labeled "Trump Ice Natural Spring Water." The package reportedly included a note that said, "Since you're always sweating, we thought you could use some water." Ouch.

(Credit: Getty Images / Al Bello, Getty Images)

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Donald Trump on Carly Fiorina

"Look at that face!" Donald Trump once said of Carly Fiorina, according to a September Rolling Stone profile. "Would anyone vote for that? Can you imagine that, the face of our next president?!"

He later admitted on "Fox and Friends" that he "probably" did say that, but explained, "I'm talking about persona, I'm not talking about [looks]."

(Credit: Getty Images / Chip Somodevilla, Getty Images / Sean Rayford)

Donald Trump on Rand Paul

Donald Trump threw a ton of shade at

Donald Trump threw a ton of shade at the second GOP debate when he remarked, "Rand Paul shouldn't even be on this stage. He's number 11 [in the polls]."

(Credit: Getty Images / Mandel Ngan, Getty Images / Sean Rayford)

Donald Trump on Jeb Bush

Donald Trump has repeatedly taken jabs at Jeb

Donald Trump has repeatedly taken jabs at Jeb Bush, calling him low-energy and weak on immigration.

The Donald said on CNN's "State of the Union" Sunday, "Obviously, [Bush is] no longer the front-runner. I probably won't talk about him so much anymore."

Still, Trump went on to call Bush's campaign a "total disaster."

(Credit: Getty Images / Scott Olson)

Donald Trump on George Pataki

Donald Trump went after George Pataki ahead of

Donald Trump went after George Pataki ahead of the second Republican debate.

"Why is someone like George Pataki, who did a terrible job as Governor of N.Y. and registers ZERO in the polls, allowed on the debate stage?" Trump mused on Twitter.

Pataki was quick to respond.

"Why is a serially bankrupt @RealDonaldTrump who insults Mexicans, Women, Blacks, Jews & POW's on #2016 debate stage? #TajMahal #TrumpCastle," he tweeted.

(Credit: Getty Images / Steve Pope, Getty Images / Scott Olson)

Donald Trump on Lindsey Graham

Donald Trump called Lindsey Graham a

Donald Trump called Lindsey Graham a "total lightweight" at a July rally in South Carolina after Graham dubbed Trump a "jackass" for saying that Sen. John McCain wasn't a war hero.

Trump also dismissed Graham as registering "zero in the polls" before claiming that Graham had asked Trump for help getting an interview on "Fox and Friends."

Then, in an unexpected twist, Trump recited Graham's personal cellphone number.

(Credit: Getty Images / Mark Wilson, Getty Images / Scott Olson)

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