Critics had expressed concern that impersonating others would become easy on the platform after Musk said anyone would be able to purchase a verification checkmark.
Sure enough, personalities decided to impersonate Musk by changing their names and profile pictures.
Comedians Sarah Silverman and Kathy Griffin and actor Rich Sommer were among those who wanted to show the billionaire just how easy it was to do so.
Their accounts were soon suspended, with Silverman's remaining "locked."
When Musk took over the social media app, he tweeted about comedy being legal now. Last Sunday, he said: "Going forward, any Twitter handles engaging in impersonation without clearly specifying "parody" will be permanently suspended."
On Friday, he added that accounts engaging in parody "must include 'parody' in their name, not just in bio."
"To be more precise, accounts doing parody impersonations. Basically, tricking people is not ok."