[Ads /]
A series of video clips show the altercation at the McDonald's at North State Street and West Chicago Avenue Monday night.
The man who filmed them, who asked to have his name withheld, was there with his girlfriend at the time.
He pulled out his cellphone and recorded the moments after the confrontation began.
Hannah Walker, 36, is facing a misdemeanor battery charge.
She is seen in the video swinging a hammer at 16-year-old Jasmine Ware, hitting her in the face.
"The only one who seemed to be getting in the middle of it was a security guard," the witness said.
Ware said the woman started fighting her and her friends about their place in line.
"She just got loud, yelling, bumping us, doing all types of stuff," she said.
[Ads /]
The man who recorded the video can't believe a stop at McDonald's for ice cream turned into this.
"I actually left before police came, after about 45 seconds to a minute, maybe a little longer. I got nervous that someone was going to pull out something more dangerous, supposedly a gun," he said.
Chicago police are reviewing the cell phone video.
WLS reached out to the teen who was hit with the hammer and sent her the video.
She said the clips don't tell the whole story, but said you can clearly see she was hit with a hammer.