As President Trump sets about shrinking the government, he has repeatedly claimed that popular safety net programs, including Social Security and Medicaid, are off the table, and spoken about them delicately.

During a three-hour interview with the podcast host Joe Rogan on Friday, it seemed as if Elon Musk hadn’t gotten that memo.

“Social Security is the biggest Ponzi scheme of all time,” Musk declared.

The moment offered an immediate opening for Democrats, who accused Musk of looking to cut benefits for older and disabled people. And it created a fresh headache for Republicans who have labored to explain how they plan to cut the budget drastically without slashing popular programs like Medicaid.

These are the remarkable and at times surreal risks inherent in Trump’s decision to turn his presidency into a kind of co-production with a world-famous, often undisciplined billionaire. And the interview laid them bare.

The appearance — Musk’s most extensive solo interview since the beginning of Trump’s second administration — offered a window into his worldview that was by turns crude and contradictory. Musk defended his efforts with his Department of Government Efficiency, alternatively casting it as existential and downplaying its scope, while expounding on not-safe-for-work interests like A.I. sex robots.

Here are some takeaways from the conversation.

Musk acknowledged he has far-reaching goals.

Musk repeatedly acknowledged just how radical his aims are, calling his project of slashing the government work force, cutting contracts and eliminating regulations a “revolution” against the federal bureaucracy.