Rob Kardashian may have hit a new low with his latest move.

After the reality star learned his fiancée and mommy-to-be Blac Chyna wasn't invited to a baby shower being thrown for their unborn daughter, Rob blasted sister Kylie Jenner's number on Twitter, in addition to sharing a not-so-nice message to the 19-year-old.

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"Didn't invite the mother of my child to a baby shower you were all trying to throw for me?! You must have lost your damn minds," he wrote in a separate tweet.

rob kardashian kylie jenner tweet

Rob, who tweeted Kylie's phone number twice, insisted his account wasn't hacked, "I ain't hacked, this is Rob dog," he tweeted.

Chyna, who's pregnant with a baby girl, has had a hot-and-cold relationship with King Kylie since the 19-year-old began dating her ex Tyga. The two seemingly made amends during sister Khloé Kardashian's 32nd birthday, but after this harsh snub, their feud is still alive and well.