Welcome to Saint West's Jurassic World!
Kim and sister Khloe Kardashianposted adorable photos and videos from the bash on her Instagram page, including a clip of the guest of honor wearing a carnivorous dinosaur mask handed to him by big sister North West, 6, and momentarily scaring his 1 and 1/2-year-old little sister Chicago West.
"Don't be scared, Chi-Chi, it's just your brother with a mask," Kim tells her.
"It's just Sainty," Saint says.
The outdoor bash was decorated to look like a jungle, complete with a nest of fake dinosaur eggs, lush greenery and a fog machine, which intrigued little True.