"Gwen Stefani is really the worst thing to ever happen. Period. Full stop. #UghBarf," a fan tweeted to the singer.
Miley Cyrus, meanwhile, responded to her mean tweet by sticking out her middle finger towards the camera. "Miley Cyrus is a smelly pirate hooker," she read.
The Chainsmokers, Tyga, Imagine Dragons, Halsey, Jason Mraz, Luke Bryan, Jason Derulo, Dua Lipa, The Strokes, Pink, Elvis Costello, Schoolboy Q, G-Eazy, Luke Combs, Korn and Nickelback were also featured.
"Peep the fact that Luke Combs looks like the guy who changes your oil at Jiffy Lube," the country star read from Twitter.
Taylor Swift broke the record for most AMA wins by a female artist after taking home Artist of the Year, Tour of the Year, Best Pop/Rock Female Artist and Best Pop/Rock Album for Reputation. Other big winners included Camila Cabello and Post Malone.