Elon Musk’s war on MAGA has quickly gone nuclear after the billionaire CEO blasted a social media user’s comments about HB1 visas Friday, and former Trump chief strategist Steve Bannon called him a “toddler” for his response.

The Tesla billionaire, chosen by Donald Trump to be co-head of his new Department of Government Efficiency (DOGE), has infuriated anti-immigration elements of the Republican Party by defending the H-1B visa, which permits highly educated foreigners to work in the US for up to six years.

Less than a month before Donald Trump returns to office, two of his most ardent allies have plunged into a fierce online debate over immigration, specifically the government’s visa program that allows American companies to hire so-called “highly skilled” foreign workers.