Rob Kardashian and Blac Chyna had some fun at Kris Jenner's expense on Instagram — but Kim Kardashian wasn't about to let it slide.

Earlier this year, the famous momager stocked the 29-year-old reality star's new pantry with a variety of goodies, and instead of being grateful, he joined his 27-year-old fiancée in making fun of some of the unhealthy food choices in a series of mean-spirited videos.

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"You're blasting mom, it's petty as f–k!" Kim told her younger brother over the phone in a preview for next week's episode of KUWTK.

rob kardashian kim kardashian blac chyna getty

Kris also saw the "disrespectful" videos on social media, and wasn't happy with her son and future daughter-in-law.

"Rob went on his Instagram and was making fun of the food I bought," the 60-year-old grandmother told daughter Kourtney Kardashian in the clip.

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Though Rob eventually deleted the videos, this isn't the first time the controversial couple has insulted a member of his famous family. Just last week, Chyna released an emoji of a Kylie Jenner look-alike getting slapped in the face.