Best auntie ever!

On Saturday Kim Kardashian squeezed her pregnant body into a tight white number and picked up her nephew Mason for a day of shopping at Toys 'R Us. Mason obviously scored a ton of goodies, but Kim picked out a bunch of mermaid toys for daughter North and Mason's little sister Penelope.

While in St. Barth last week the girls had an encounter with a "real-life" mermaid at the pool, and they're clearly obsessed! From The Little Mermaid dolls to pool games, Kim clearly went all out when she shopped at the store. While we doubt Kim will be modeling mermaid couture anytime soon, Nori and Penelope certainly had it down pat: