Both moms took to Snapchat to document the Monsters Inc.-themed celebration, which included a ton of winter-appropriate outdoor activities like ice skating, sledding (on fake snow) and a visit from Santa Claus.
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Kim, 37, shared an adorable shot of her husband Kanye West gently leading Saint and the couple’s daughter North, 4, towards the ice-skating rink, above which hung a string of twinkly lights and the words “Merry Monster Mash” spelled out in silver balloons.
Kim and Kourtney, 38, also surprised the two boys with their own individual confections, themed after the two BFFs from the films: a James P. “Sulley” Sullivan cake for Reign, and a Mike Wazowski cake for Saint.
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This isn’t the first time the Disick-West cousins have celebrated their birthdays together — and Disney seems to be a common theme!
And in 2016, the two girls celebrated with a mermaid-themed bash.