It's insane -- according to the report, obtained by TMZ, cops were called to an apartment parking lot around 9:45 PM on Saturday night ... after Michael Lohan's ex-GF was observed beating the crap out of a man and his wife.

Cops say ... when they arrived to the scene, Major was being restrained on the ground by several people who saw her attack Rosario Tapia and Juan Jimenez.

The officer who wrote the police report explained, 'I attempted to speak with Major, who was screaming and yelling obscenities at Tapia, calling her a 'fat f**k' and a 'b*tch'."

Jimenez told police ... he has NO IDEA why he and his wife were attacked ... but explained he and Tapia pulled into the parking lot and noticed someone had parked in their assigned space. So they were waiting for another spot to open ... when Major came bolting towards the car out of nowhere.

Jimenez claims Major opened the door and went crazy -- calling him and his wife "several racial names" before Major attacked his wife in the hands, breast and face.

When cops tried to arrest Major, police say she resisted arrest and tried to kick the officers.

Major was eventually arrested for battery and transported to a nearby jail -- where she was an EVEN BIGGER pain in the ass, according to the report.

Cops say she yelled at police -- and tried to make a break for it. At one point, cops say, she slapped the arresting officer and called him a "fat f**k."

She was later charged with resisting arrest with violence and battery on a police officer.