Bill Kristol, editor of the conservative Weekly Standard, posted a cryptic tweet over the weekend promising a third party alternative would soon emerge to challenge Donald Trump and Hillary Clinton.

Just a heads up over this holiday weekend: There will be an independent candidate–an impressive one, with a strong team and a real chance.

— Bill Kristol (@BillKristol) May 29, 2016

Trump, of course, just couldn’t contain his own impulsive Twitter behavior and launched into Kristol with his typical middle-school mannerisms. (Notice the time stamps — these were all posted within ten minutes. Trump is seriously unstable, but I digress.)