Donald Trump, get ready to feel the Bern.

Senator Bernie Sanders appeared on Conan Tuesday and fielded questions from the late night host about the President-elect’s tweeting habits.

Conan O’Brien asked the former presidential hopeful about Trump’s tweet in which he claimed millions of people voted illegally.

“First of all, it’s delusional,” Sanders said. “It’s totally insane. Nobody believes that who studies elections or election patterns. But number two; this is what is scary about it. When he says that, he’s really sending a signal to Republicans all over the country – Republican leaders – and what he’s saying is we have got to suppress the vote. We have got to make it harder for poor people, people of color, immigrants, elderly people to participate because they may be voting against us, and that’s scary stuff.”