'Petty As F**K!' — Kim Kardashian Blasts Rob In Shocking Showdown

Kim Kardashian went after her brother Rob in a vicious phone call, and it was all caught on camera in a sneak peek video for Sunday's new episode of Keeping Up with the Kardashians.

"My mom told me about Rob making fun of all the food my mom bought him," Kim, 35, explained of how the latest family dustup started after he dissed Kris Jenner on social media, even though the matriarch was doing her best to help him lose the unhealthy pounds he had packed on.

"I mean, my mom literally just helped him move into a new house. I have to call my brother out on this," continued Kim. "Like, there's no way I'm going to let my brother disrespect her."

Once she got started, Kim, who insisted she almost never got upset and only wanted the best for 29-year-old Rob, couldn't resist spelling out some other issues she had. Kanye West's wife let her sibling know she was also displeased with how Blac Chyna was constantly dissing Kylie Jenner.

"When you start publicly bashing my sister and mom, that's not cool. This is just unnecessary, this is not what our family does," blasted Kim. "There's way too much drama, so many haters in the world – we don't need it from our own inside circle."

Though her complaints seemed to fall on deaf ears, Kim added: "Everyone has to just not be blasting people on social media. You and Blac are a unit now, so it looks like you're blasting mom, and it's petty as f**k."