President Trump’s first social media manager had a singular reaction when he realized in 2013 that the future president had finally figured out how to use Twitter all on his own.

“The moment I found out Trump could tweet himself was comparable to the moment in ‘Jurassic Park’ when Dr. Grant realized that velociraptors could open doors,” recalled Justin McConney, who was the Trump Organization’s director of social media from 2011 to 2017. “I was like, ‘Oh no!’”

The fateful moment — Trump as of Thursday had 56.4 million followers on his official POTUS account — came that February after Trump tweeted to thank actress Sherri Shepherd for saying nice things about him on TV.

“Thanks @SherriEShepherd 4 your nice comments today on The View. U were terrific!” he tweeted, McConney told Politico.

When he saw the tweet, he was confused, McConney told the website, because he usually typed and sent tweets for the boss.

He then quickly checked with other staffers to see if they had subbed for him before realizing that Trump had finally figured out how to use his Android.

McConney, who left the Trump Organization last year, told the story of Trump’s evolution from technophobe to social media sensation — for better or worse.

He also had advice for his former boss as he heads toward the 2020 elections.

“He needs to return to engaging directly with his fans again,” said McConney, a social media consultant. “He should be livestreaming from the Oval Office.”

When Trump first learned about Twitter, he was curious.

“I’ve heard of that. Isn’t that what Obama used?” he said, according to McConney.