A "Medicare for all" T-shirt is 2018's “scariest Halloween costume,” according to the head of Medicare and Medicaid.

“This year’s scariest Halloween costume goes to…,” Centers for Medicare and Medicaid Services Administrator Seema Verma tweeted Wednesday afternoon, along with an accompanying image.

Verma has been vocal in her criticism of “Medicare for all.” Earlier this month, she said the proposal is not something the country can afford, and said expanding Medicare will threaten seniors' security.

“The Medicare program is intended and designed for seniors and we need to do everything we can to strengthen the program for seniors,” she said at the Atlantic Festival in Washington.

[More: Seema Verma takes swipe at 'Medicare for all' by tying it to Obamacare's problems]

Sen. Bernie Sanders, I-Vt.,first introduced the Medicare for All Act in September 2017 to enroll all Americans in the federal healthcare program, abandoning employer-provided insurance.

“Medicare for all” has gained popularity among Democratic candidates for the 2018 midterm elections, including from Alexandria Ocasio-Cortez, who defeated incumbent Rep. Joe Crowley, D-N.Y., in a primary race in June.