The other 2020 presidential candidates have not held back when it comes to Bloomberg after he made his late entry into the race. Former Vice President Joe Biden has questioned his status as a Democrat (Bloomberg changed his registration to run for NYC mayor as a Republican in 2001 — and switched back to Democrat about, uh, a minute ago), and others have accused him of trying to buy his way to the nomination. After Bloomberg qualified for the debate, his first, Sen. Elizabeth Warren tweeted that "at least now primary voters curious about how each candidate will take on Donald Trump can get a live demonstration of how we each take on an egomaniac billionaire." Pretty much everyone else on-stage at the debate on Wednesday — Biden, Warren, former Mayor Pete Buttigieg, Sen. Amy Klobuchar , and Sen. Bernie Sanders — took a jab or several at Bloomberg.