U.S. Sen. Elizabeth Warren is sounding the alarm with her Democratic base, warning a Senate run by Detroit bad boy Kid Rock could be the second coming of Donald Trump.

The “Wasting Time” and “All Summer Long” rap rocker-turned-country singer tweeted on Wednesday that he’s running for U.S. Senate in Michigan. Although it’s been largely dismissed so far as a publicity stunt, Warren isn’t taking any chances with the longshot Republican.

“I know a lot of people are thinking: this is some sort of joke, right?” Warren wrote in an email blast with the subject line “Senator Kid Rock (R-MI).”

“Well,” she said, “maybe this is all a joke — but we all thought Donald Trump was joking when he rode down the escalator at Trump Tower and announced his campaign, too.

“And sure, maybe this is just a marketing gimmick for a new album or tour — but we all thought Donald Trump was just promoting his reality TV show, too,” she added.