Simona Fusco -- who played Ulsa, the hot cheerleader in "Beerfest" ... went from victim to alleged criminal in a matter of moments ... ARRESTED for a suspicious white powder in her purse.
Fusco was at Mastro's restaurant in Bev Hills just after midnight Saturday when 2 men started fighting for her attention. It got so rowdy, cops were called. Law enforcement sources tell TMZ ... when they arrived, they tried to speak with her when she shoved one of the cops.
The shove changed everything. Police placed her under arrest and did the obligatory search. When they went inside her purse they say they found a mysterious white powder and that's all she wrote.
Fusco -- who also appeared in "Bottoms Up" and as hot girl in "Entourage" -- was arrested for possession of a controlled substance. If the substance turns out to be an illegal drug, the stakes will probably go up -- to possession of (fill in the blank).
We reached out to Fusco's reps ... so far, no comment.