Washington (CNN) The administrator of the nation's federal health insurance programs tweeted a Halloween-themed message bashing "Medicare-for-all," a policy pushed by some Democrats.

Seema Verma, who runs the Centers for Medicare and Medicaid Services, wrote Wednesday on Twitter: "The year's scariest Halloween costume goes to..."

The tweet then featured an image of an individual wearing a T-shirt with the words "MEDICARE FOR ALL" printed across the front.

This year's scariest Halloween costume goes to... pic.twitter.com/QtRbdmiR8T — Administrator Seema Verma (@SeemaCMS) October 31, 2018

"Medicare-for-all" is a proposal that would broaden Medicare, which provides coverage for seniors and some people with disabilities, to all Americans in an effort to reduce the uninsured rate.

The idea has been widely embraced by progressives such as Sen. Bernie Sanders, an independent from Vermont who caucuses with the Democrats and is one of the driving forces behind its current momentum. He rolled out a proposal during his unsuccessful 2016 presidential bid and introduced a new "Medicare-for-all" health care bill last fall with a third of the Senate Democratic caucus by his side.

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