Republican strategist Matt Mackowiak has some strong words for Donald Trump. On the evening of the presidential election, Mackowiak unleashed a 15-part Twitter rant attacking the Republican nominee.

Mackowiak, who is the founder of conservative political communications firm Potomac Strategy Group and frequently appears on Fox News, called his rant a “Trump real talk tweet storm.” In his first tweet, he tells Trump to “Go f**k yourself. You just conceded the most winnable election in 50 years against the least popular Dem nom ever,” a reference to Democratic nominee Hillary Clinton.

And he didn’t stop there. The high-profile conservative continued over the next 15 minutes with the following:

Whew.