On May 2, 2020, U.S. President Donald Trump appeared to have posted a tweet to his official Twitter account in which he called MSNBC host Nicolle Wallace a "dog" and a "3rd rate lapdog for Fake News MSDNC."
The tweet generated news stories, including one from Deadline, which reported in its headline that Trump had launched a "vicious personal attack" on Wallace, prompting readers to ask whether the post was real.
The tweet is indeed real and can be found on Trump's verified Twitter account (archived here):
Trump was responding to commentary from conservative podcaster Mark Levin who accused Wallace of hypocrisy in regards to her take on sexual assault allegations against Joe Biden.