"You think she hit her? You're so full of sh*t. You're a pathological liar," Pratt screams at the former Real Housewives of New York starlet, presumably defending his 28-year-old wife.
After a vase mysteriously shatters, Pratt, 31, continues on his rant against Aviva, 44, and the WE tv series' executive producer.
"You're making her feel guilty for something that she didn't do! We were all there!" he fumes, before directing his rage toward Aviva's husband.
"Hey Reid, you are so not what I thought you were, you fake a** fool," he slams.
"You're a b*tch just like your wife!"
The outspoken Montag doesn't let her husband do all the hating for her.
"Everybody knows she's a c*nt and he's a b*tch and f*ck them both!" she snarls as she exits the room.
The plastic surgery enthusiast further unloads on the infamous Bravolebrity in her confessional interview.
"There's only person who's a hater in this house, and it's a little liar named Aviva," she tells the cameras.
"It makes me so mad that someone can be such a disgusting, horrible, awful person and liar."
Are you Team Heidi or Team Aviva? Sound off in the comments, watch the exclusive clip below, and tune into Marriage Boot Camp: Reality Stars this Friday at 9 pm on WE tv.