Comments included a mock Google translation of "covfefe" from Russian into English as "I resign", and comments like "Drain the covfefe" - a play on Trump's promise to "drain the swamp" in Washington.
Members of the press then asked Spicer what Trump meant by the tweet, in particular wondering what "covfefe" means.
"Despite the constant negative press covfefe", read the U.S. leader's short tweet. "(We) understand more than most that sometimes it is necessary to use code words".
However, Trump seemed to enjoy the fuss and later tweeted: "Who can figure out the true meaning of "covfefe"???".
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Giving a fuller answer this time, Spicer said: "No, I think the President and a small group of people know exactly what he meant".
It received more than the usual level of interest attracted by Trump's tweets.
"Last night for five blessed hours, Donald Trump made America truly great", Samantha Bee said on Wednesday's episode of TBS's "Full Frontal" right before playing clips from media discussing the president's tweet.
The White House says President Donald Trump will welcome the president of Romania to the White House next week.
In case you still don't know what we are talking about, this is Trump's tweet.
Team Twitter already had gone into overdrive trying to fill in the blanks, floating both silly and serious scenarios.