Billionaire Chris Sacca isn’t mincing words about the Republican plan to dismantle Obamacare.

The tech entrepreneur and former Shark Tank investor (Sacca announced his exit from the venture capital field earlier this year) took to Twitter to encourage Americans to call their lawmakers in a bid to kill the GOP’s health care bill. The U.S. Senate released its initial draft of the legislation on Thursday (you can read my initial analysis of the bill and its prospects here).

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Sacca says that the legislation will essentially amount to a gigantic wealth transfer from the poor to the rich. That’s more or less the conclusion that independent analyses from organizations like the Congressional Budget Office have reached about the House-passed American Health Care Act (the CBO says that bill would amount to 23 million fewer insured and higher out-of-pocket costs for the elderly, low-income people, and the medically needy). The Senate’s Better Care Reconciliation Act differs from the AHCA in several ways, but would also scale back subsidies to the poor and take a hacksaw to Medicaid, the safety net program that insures low-income people.

The medical industry has also been critical of the AHCA, and the Senate’s bill may not prove much more popular. The AARP, the nation’s largest advocacy group for the elderly, slammed the legislation in a statement on Thursday.

“This new Senate bill was crafted in secrecy behind closed doors without a single hearing or open debate—and it shows. The Senate bill would hit millions of Americans with higher costs and result in less coverage for them,” the group wrote. “AARP is adamantly opposed to the Age Tax, which would allow insurance companies to charge older Americans five times more for coverage than everyone else while reducing tax credits that help make insurance more affordable.”

It’s unclear whether or not the legislation can carry the requisite 50 votes for passage, and if a compromise can be reached with the House after that. At least four conservative Senators have already expressed opposition to the Senate’s bill, and only three GOP “no” votes would be required to sink it.