Musk posted a video of himself carrying a ceramic bathroom sink into the lobby of the headquarters.
The billionaire wrote in the caption that he was amused by his own father joke.
It comes on the heels of months of chaotic negotiations, drama in the courts, and Musk's repeated and increasingly desperate attempts to get out of the deal he signed with the social media company.
The employees only got a short notice of Musk's visit. Elon is in the SF office this week meeting with folks, walking the halls, and continuing to dive in on the important work you all do.
"If you're in SF and see him, say hello!" the email says. "For everyone else, this is just the beginning of many meetings and conversations with Musk, and you will hear directly from him on Friday," said the statement.
Musk told co-investors that he would close his deal on Friday. The acquisition price was close to the original one.
There is a lot at stake. The Washington Post reported last week that Musk is going to fire up to 75% of the staff.
The company has some rocky weeks and months ahead of it and employees only have days for a new reality to sink in.
There is more on the debacle.