WATCH: Warren sets her sights on Bloomberg’s taxes -- after shaming him on Non-Disclosure Agreements
Presidential candidate Elizabeth Warren speaking at the Democratic National Convention summer session in San Francisco, California. (Sheila Fitzgerald/Shutterstock)

During a campaign speech in Seattle on the night of the Nevada Caucus, Sen. Elizabeth Warren (D-MA) tore into former NYC Mayor Michael Bloomberg as an "arrogant billionaire."

Warren warned about "a threat that is coming our way."

"It's a big threat. Not a tall one, but a big one -- Mike Bloomberg," she joked, as the crowd booed.

She argued the billionaire would be the "riskiest" choice for Democrats to pick to take on President Donald Trump.

After Warren successfully shamed Bloomberg into releasing three women from Non-Disclosure Agreements in the last debate, she turned her attention to Bloomberg's tax returns.

"And here's the problem, he's hiding his taxes, he doesn't want you to see them until after the election -- who knows what lurks there?" Warren said.