Greta Thunberg may be the world's savviest Twitter troll. Here are the presidents and pundits she has put in their place.

• At 16 years old, Greta Thunberg has become the face of the youth climate movement. On Wednesday, Time magazine named her the 2019 person of the year.
• President Donald Trump criticized Time's choice as "ridiculous," tweeting that Thunberg has an "anger-management problem" and needs to "chill."
• Thunberg changed her Twitter bio to include Trump's insults.
• Earlier this week, Thunberg had a similar interaction with Brazilian president Jair Bolsonaro, who called the teenager a "little brat."
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Usually, Greta Thunberg's Twitter bio reads: "16-year-old climate and environmental activist with Asperger's." But these days, that bio seems to be in constant flux, depending on which world leaders insult her.

On Tuesday, Thunberg's bio simply said "pirralha." That translates to "little brat" or "pest" in Portuguese - a reference to comments Brazilian president Jair Bolsonaro made about her.

Today, Thunberg's bio reads: "A teenager working on her anger management problem. Currently chilling and watching a good old fashioned movie with a friend."

The change came after President Donald Trump said in a tweet that Thunberg "must work on her Anger Management problem, then go to a good old fashioned movie with a friend! Chill Greta, Chill!"

Trump's tweet came after the news that Thunberg was named Time magazine's 2019 person of the year - a title for which Trump was also in the running.

These social-media tactics are the latest in a series of Thunberg's clever clap-backs at her critics. In short, she's mastered the art of being a Twitter troll.

Thunberg has trolled Trump before

In September, after Thunberg gave a fiery, impassioned speech to UN leaders, Trump mockingly tweeted: "She seems like a very happy young girl looking forward to a bright and wonderful future. So nice to see!"

Less than 24 hours later, Thunberg hit back by changing her Twitter bio to: "A very happy young girl looking forward to a bright and wonderful future."

Bolsonaro's recent "pirralha" comment, meanwhile, came after Thunberg denounced the killing of indigenous Brazilian people in the Amazon in a tweet on Sunday. She included a video of a drive-by shooting that left two indigenous leaders dead in Maranhão, Brazil.

"Indigenous people are literally being murdered for trying to protect the forest from illegal deforestation. Over and over again," Thunberg wrote on Twitter. "It is shameful that the world remains silent about this."

Bolsonaro was clearly irked.

"Greta's been saying Indians have died because they were defending the Amazon," Bolsonaro told reporters in Portuguese on Tuesday. "It's amazing how much space the press gives this kind of 'pirralha.'"

In October, Russian president Vladimir Putin also weighed in on Thunberg. At an energy forum in Moscow, Putin said he did not share "the common excitement" about her, though eh added that he is "sure that Greta is a kind and very sincere girl."

Thunberg once again leapt into action, changing her Twitter bio to read: "A kind but poorly informed teenager" - a reference to Putin's platitude.

'They must simply feel so threatened'

Many pundits, including US conservative commentator Michael Knowles, have also criticized Thunberg.

The night after Thunberg's speech at the UN in New York, Knowles appeared on Fox News's "The Story" and called Thunberg "a mentally ill Swedish child." Fox later apologized.

That time, Thunberg tweeted a long thread that did not acknowledge Knowles by name, but called out "the haters."

"As you may have noticed, the haters are as active as ever - going after me, my looks, my clothes, my behaviour and my differences," she wrote. "I honestly don't understand why adults would choose to spend their time mocking and threatening teenagers and children for promoting science, when they could do something good instead. I guess they must simply feel so threatened by us."

At the culmination of the same UN climate summit, Thunberg joined 15 other children in filing a legal complaint stating that five countries' inaction to address climate change violates the UN Convention on the Rights of the Child. The countries named were Argentina, Brazil, France, Germany, and Turkey.

French president Emmanuel Macron pushed back against Thunberg after that, telling Europe 1 that her position was "very radical" and likely to "antagonize societies."

"All the movements of our youth - or our not-so-young - are helpful," Macron said. "But they must now focus on those who are furthest away, those who are seeking to block the way."

The president added that he didn't feel "that the French government nor the German government, currently, were blocking the way."

The next day, Thunberg retweeted a video posted by UK television personality Mark Humphries titled, "THE GRETA THUNBERG HELPLINE: For adults angry at a child."

The video stars a man who admits he's "irrationally angry at a Swedish girl who wants to save the planet."

A patient female operator explains in the video: "If you're a grown adult who needs to yell at a child for some reason, the Greta Thunberg Helpline is here to tolerate you."