The 'Easy A' actress reportedly lashed out at a Bobby Cohen and had to be calmed down by security at the Revel Resort in Atlantic City, New Jersey.
His son Brett Cohen told gossip website RadarOnline.com: "She was stumbling and reeked of alcohol.
"She was carrying a huge handbag and something that looked like a pet carrier but I was hoping there wasn't an animal inside because of the way she was holding it."
He claims that when his father tried to take a picture of the troubled starlet she instantly freaked out.
He said: "She started yelling at my dad and lunging at him. I told her 'Amanda, you can't do that, leave him alone' and she just freaked out screaming, 'he can't take my picture'.
"A couple of security men came by and tried to calm her down and keep her from my dad. They had no idea who she was other than someone who was acting like a crazy person."