The star took to Instagram with a selection of images from Halloweens gone-by and Rob dressed as a vampire was adorable.
It was almost impossible to recognize him as he appeared to be about six years old and had a full face of white makeup, false teeth and fake blood dripping down his face.
Rob wore a cloak and white gloves and had his hair slicked back like Dracula. "Some of my favorite Halloween memories," Kris wrote and added further photos of all of her children, Kim, Khloe and Kourtney Kardashian, and Kendall and Kylie Jenner too.
Fans loved the throwbacks and urged Kris to share more photos of Rob, as he's rarely seen. "More Rob content please," wrote one, while a second said: "Look at Rob," while some said they didn't realize it was him.
Others remarked on the resemblance between Rob and his nephew, Reign, who is Kourtney's son. "I thought Rob was Reign until I clicked on the tag," said one of Kris' social media followers, as another quipped: "Rob is Reign!"
The Kardashians is currently back on Disney Plus, but Rob is noticeably absent from the reality TV show.
He stepped away from the limelight many years ago and is focused on raising his daughter, Dream, six, who he shares with his ex-girlfriend, Blac Chyna.
While he hasn't publicly said whether he'd like to return to the show, his sister, Khloe, insists it could happen. During a recent episode, she said: "I do think Rob will come back to the show. He talks about it a lot. He does."
"But I do know Rob has been through a lot personally, but he's literally the best dad that I know, and I'm so proud of him for that. He's just feeling really good about himself. So I have faith that soon he'll be back on the show."
Rob has also been focusing on his health after being diagnosed with type 2 diabetes in 2015 and is dedicated to his wellbeing and caring for Dream - and fatherhood suits him.
Kris Jenner told the Pretty Messed Up podcast in 2020, that Rob is "so in love" with his daughter, who turns seven next month. "He's such a great dad and you never know," she said. "You have kids, they grow up, they have their kids and you just don't know how somebody is going to be as a parent, but he's just, wow."
Blac also has great things to say about Rob, despite their messy breakup and lawsuit. They now co-parent Dream and share custody.
"I feel like with everything time heals everything," the model said. "People change, and situations change, and you get to see the situation for what it is, and the situation is Dream."
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