Biotech CEO Bryan Johnson is going to war with Elon Musk after the billionaire mocked his intense antiaging routine

• Both Bryan Johnson and Elon Musk want to change the world. 
• But Johnson isn't a fan of Musk. 
• The biotech entrepreneur slammed Musk after the latter mocked his antiaging routine. 

Bryan Johnson may have expansive ambitions like Elon Musk, but the biotech CEO isn't a fan of the mercurial billionaire.

"The difference between Elon and me: I'll nourish you and drink your blood; he'll fire you and leave you to die," Johnson wrote on X on Sunday.

Johnson appeared to be referencing the mass layoffs at Twitter after Musk took over the platform.

Johnson had slammed Musk after the latter appeared to mock his appearance and antiaging routine last week. Musk had agreed with an X post saying that Johnson had looked better before he altered his lifestyle.

Johnson had initially struck a self-deprecatory tone in response to Musk's comment.

"Former Bryan didn't get invited to vampire cosplay as himself," Johnson wrote on Saturday.

But it looks like Johnson is done playing nice with Musk.

"Like invisible ink, norms remain invisible until provoked," Johnson told X user Frank Chen, who had chastised him for picking a fight with Musk.

The biotech entrepreneur is best known for his desire to prolong his lifespan. Johnson said he spends about $2 million yearly to reverse his biological age.

Johnson's quest for youth has seen him participate in bizarre experiments. He briefly infused himself with blood from his son to slow down his aging.

Johnson stopped the transfusions after six months, saying there were "no benefits detected."

Representatives for Johnson and Musk did not immediately respond to requests for comment from Business Insider sent outside regular business hours.