As with most fights, this one started stupidly, escalated quickly and ended sadly. (Watch the video below.)
And to think it all started with a scepter, which Moore, 43, wielded as the reunion began.
"Queens carry those," she said, before "knighting" host Andy Cohen.
But Williams didn't take kindly to Moore turning the royal prop on her, saying, "Bitch, stop pointing that thing at me."
"I would like Porsha to spell scepter," Moore taunted her. "Go."
Williams eventually yanked the scepter from her hand and tossed it on the floor, but tempers really escalated when talk turned to whether Moore's rumored royal boyfriend was real.
"It's just very clear that there is no African prince for you," Williams said. "You just recently tried to pay someone to be on the show."
Cue another prop from Moore, who brought out a megaphone.
"If you blow that, there's gonna be real problems," said Williams, 31. "You have been a villain from day one."
"Excuse me, I'm talking," Moore screamed into the megaphone. "Please be quiet."
But neither took that sage advice, and when Moore accused Williams of cheating on former husband, Kordell Stewart, all hell broke loose.
"You're a slut from the '90s," said Williams.
"You are a dumb ho, shut up," Moore yelled into the megaphone, prompting Williams to stand up and get in her face.
"I'm going to get you fired," Moore said, as Williams tried to grab the megaphone from her. "Get fired."
With that, Williams grabbed Moore's hair, pulling her down and dragging her across the floor, all while Cohen was frantically screaming, "No! No! No! Stop!"
"Porsha, you're done," Moore said as she stood and walked off, "She should be fired."
Moore seemed in shock as she lay on the floor surrounded and comforted by the housewives, and would later tell Cohen she had blacked out during the fight.
"I've been through so much!" she cried, before screaming, "I can't believe I did that!" stomping her feet in a low-cut, sequined gown, as NeNe Leakes covered her mouth with her hands.
"I have embarrassed myself," Williams sadly stated, adding as she was carried off the stage, "I can't believe that wretched ho made me go there."
Cohen visited Williams and Moore in their dressing rooms, telling Williams, "You understand to get physical is not the way? At some point, you need to apologize," before sending her home to take care of herself.
Part two of the reunion continues without Williams on Sunday (8 p.m. ET) on Bravo.